Long-Term Debt - ABL Facility due July 2027 (Details)	Apr. 12, 2018 USD ($)
ABL FILO Facility \| Minimum \| Commitment Fee Percentage One
Debt Instrument [Line Items]
Unused commitment fee	0.25%
ABL FILO Facility \| Secured Overnight Financing Rate \| Line of Credit
Debt Instrument [Line Items]
Spread on variable rate, floor	0.00%
ABL FILO Facility \| Secured Overnight Financing Rate \| Minimum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
ABL FILO Facility \| Secured Overnight Financing Rate \| Maximum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
ABL FILO Facility \| Base Rate \| Minimum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
ABL FILO Facility \| Base Rate \| Maximum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
ABL Facility \| Minimum \| Commitment Fee Percentage One
Debt Instrument [Line Items]
Unused commitment fee	0.25%
ABL Facility \| Secured Overnight Financing Rate
Debt Instrument [Line Items]
Spread on variable rate, floor	0.00%
ABL Facility \| Secured Overnight Financing Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
ABL Facility \| Secured Overnight Financing Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
ABL Facility \| Base Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%
ABL Facility \| Base Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	0.75%
Revolving Credit Facility \| ABL FILO Facility \| Line of Credit
Debt Instrument [Line Items]
Accordion feature, increase limit	$ 95,000,000
Revolving Credit Facility \| ABL Facility
Debt Instrument [Line Items]
Available	$ 850,000,000

Cornerstone Building Brands, Inc. 10-Q