Income Taxes - Components of Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Deferred tax assets	$ 191,349	$ 233,980
Less: Valuation allowance	130,641	115,172
Net deferred tax assets	60,708	118,808
Net deferred tax liability	247,121	173,998
Deferred tax assets:
Federal net operating loss carryforwards	12,615	19,334
State net operating loss carryforwards	107,303	117,236
Deferred compensation	8,240	6,873
Foreign tax credits	20,469	39,300
Alternative minimum tax credits	3,296	6,591
Accrued insurance, pension liability and other	39,426	44,646
Total deferred tax assets	191,349	233,980
Deferred tax liabilities:
Property and equipment	226,872	209,070
Intangible assets and other	80,957	83,736
Deferred tax liabilities	$ 307,829	$ 292,806