Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax liabilities:
Property and equipment	$ (208,751)	$ (178,090)
Leased assets	(73,861)
Goodwill	(72,244)	(60,305)
Customer holdbacks	(11,882)	(44,173)
Other intangibles	(11,384)	(21,034)
Other book/tax accounting method differences	(1,801)	(7,247)
Total deferred income tax liabilities	(379,923)	(310,849)
Deferred income tax assets:
Net operating loss carryforwards	78,310	52,406
Lease liabilities	74,044
Tax credits	46,621	43,572
Accruals and reserves	36,372	28,594
Stock and incentive compensation	26,045	20,627
Deferred profit on investment in unconsolidated affiliates	0	16,021
Deferred tax benefits on unrecognized tax positions	16,542	13,278
Other	3,933	1,776
Subtotal	281,867	176,274
Valuation allowance	(104,178)	(67,601)	$ (19,300)
Total deferred income tax assets	177,689	108,673
Total net deferred income tax liabilities	$ (202,234)	$ (202,176)