Leases - Net Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Net lease costs	$ (11,200)	$ (14,865)	$ (16,786)
Variable lease costs	1,500	1,600	600
Other general and administrative
Lessee, Lease, Description [Line Items]
Operating lease costs	(17,346)	(19,502)	(17,183)
Other revenue
Lessee, Lease, Description [Line Items]
Sublease revenue	$ 6,146	$ 4,637	$ 397