Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating Lease Costs
Operating lease costs before capitalized operating lease costs	$ 7,568	$ 8,622	$ 15,135	$ 16,735
Operating lease costs capitalized	(861)	(791)	(1,689)	(1,537)
Operating lease costs, net	6,707	7,831	13,446	15,198
Finance Lease, Costs [Abstract]
Interest on financing leases	1,494	2,149	2,986	3,812
Interest on financing leases capitalized	0	(1,043)	0	(1,790)
Interest on financing leases, net	1,494	1,106	2,986	2,022
Finance lease, right-of-use asset, amortization	180	305	360	610
Financing lease costs, net	$ 1,674	$ 1,411	$ 3,346	$ 2,632
Operating lease, weighted average discount rate, percent	4.55%		4.55%
Operating lease, weighted average remaining lease term	28 years		28 years