Right-of-Use ("ROU") Assets and Lease Liabilities - Operating and Finance Lease Liability (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) renewal_option	Dec. 31, 2019 USD ($)
Leases [Abstract]
Number of renewal options \| renewal_option	1
Operating leases:
Right-of-use asset	$ 123,821	$ 120,562
Operating lease liability	124,023	120,068
Finance leases included in property and equipment, net:
Vehicle and equipment ROU assets, gross	8,755	9,204
Accumulated depreciation	(4,117)	(2,562)
Total finance ROU assets, net	4,638	6,642
Total finance lease liabilities	$ 5,429	7,384
Finance lease assets, statement of financial position	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Real Estate
Operating leases:
Operating lease, right-of-use asset, gross	$ 149,365	130,746
Accumulated amortization	(42,138)	(24,743)
Right-of-use asset	107,227	106,003
Operating lease liability	107,526	105,559
Vehicles and equipment
Operating leases:
Operating lease, right-of-use asset, gross	22,280	17,416
Accumulated amortization	(5,686)	(2,857)
Right-of-use asset	16,594	14,559
Operating lease liability	16,497	14,509
United States
Operating leases:
Right-of-use asset	108,418	104,938
Operating lease liability	108,451	104,356
Finance leases included in property and equipment, net:
Vehicle and equipment ROU assets, gross	5,962	6,341
Accumulated depreciation	(3,020)	(1,892)
Total finance ROU assets, net	2,942	4,449
Total finance lease liabilities	3,335	4,777
United States \| Real Estate
Operating leases:
Operating lease, right-of-use asset, gross	130,597	114,202
Accumulated amortization	(36,719)	(21,337)
Right-of-use asset	93,878	92,865
Operating lease liability	93,995	92,319
United States \| Vehicles and equipment
Operating leases:
Operating lease, right-of-use asset, gross	19,630	14,665
Accumulated amortization	(5,090)	(2,592)
Right-of-use asset	14,540	12,073
Operating lease liability	14,456	12,037
Canada
Operating leases:
Right-of-use asset	15,403	15,624
Operating lease liability	15,572	15,712
Finance leases included in property and equipment, net:
Vehicle and equipment ROU assets, gross	2,793	2,863
Accumulated depreciation	(1,097)	(670)
Total finance ROU assets, net	1,696	2,193
Total finance lease liabilities	2,094	2,607
Canada \| Real Estate
Operating leases:
Operating lease, right-of-use asset, gross	18,768	16,544
Accumulated amortization	(5,419)	(3,406)
Right-of-use asset	13,349	13,138
Operating lease liability	13,531	13,240
Canada \| Vehicles and equipment
Operating leases:
Operating lease, right-of-use asset, gross	2,650	2,751
Accumulated amortization	(596)	(265)
Right-of-use asset	2,054	2,486
Operating lease liability	$ 2,041	$ 2,472

Foundation Building Materials, Inc. 10-Q