Lease Obligations - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lease costs
Operating lease cost	$ 120,096	$ 121,238
Amortization of finance lease assets	6,016	2,701
Interest on finance lease liabilities	2,353	1,248
Short-term lease cost	1,958	1,699
Variable lease cost	23,512	23,385
Sublease income	(1,915)	(1,876)
Net lease costs	$ 152,020	$ 148,395