v2.4.0.8

Stock Transactions Stock Transactions (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
Stock Transactions Stock Transactions (Details) (USD $)	Oct. 11, 2005	Dec. 31, 2012	Sep. 28, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Transactions [Line Items]
Initial public stock offering, date	October 11, 2005			October 11, 2005
Company contributed cash for common stock issued	$ 5,200,000
Stock issue expense, pre tax	20,700,000
Proceeds from issuance initial public offering	509,700,000
Stock subscription proceeds	557,900,000
Percentage of shares to be repurchased				10.00%
Number of shares authorized to be repurchased				3,876,523,000,000
Number of remaining shares authorized to be repurchased				2,105,036
Purchase of treasury stock, shares				83,224	60,652	2,413,455
Stock repurchased during period, value				1,531,000	902,000	32,489,000
Stock repurchase cost, per share				$ 18.39	$ 14.88
Dividends declared per share (usd per share)			$ 0.05	$ 0.20	$ 0.05
Dividends paid per share (usd per share)		$ 0.05
Common stock
Stock Transactions [Line Items]
Initial public stock offering	51,627,094
Public shares outstanding	43.74%
Investors bank employee stock ownership plan	4,254,072
Investors Bancorp, MHC
Stock Transactions [Line Items]
Initial public stock offering	64,844,373
Public shares outstanding	54.94%
Investors Bank Charitable Foundation
Stock Transactions [Line Items]
Initial public stock offering	1,548,813
Public shares outstanding	1.32%
Investors Bank
Stock Transactions [Line Items]
Proceeds from issuance initial public offering	$ 255,000,000
2006 Equity Incentive Plan \| Restricted Stock
Stock Transactions [Line Items]
Shares allocated to fund the restricted stock		3,412,701		3,415,701	3,412,701

Cash Payment Towards Refund of Stock Subscription

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Charitable Contribution Expense

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Payments for Charitable Contribution

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Stock issued during period shares new issues percentage

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Stock repurchase program, number of shares authorized to be repurchased, percentage

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Aggregate number of common shares reserved for future issuance.

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Aggregate dividends paid during the period for each share of common stock outstanding.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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This item represents the number of shares provided to the Employee Stock Ownership Plan (ESOP) during the period.

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A description of the time period when the company made its initial offering of a class of securities.

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The cash inflow associated with the amount received from entity's first offering of stock to the public.

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-Glossary Financing Activities

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Number of new stock issued during the period.

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The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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Investors Bancorp Inc 10-K