Leases - Lease Expense and Cash Outflows from Operating and Finance Leases (Details) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 9,356	$ 9,630	$ 18,780	$ 18,505
Short-term lease cost	389	279	790	513
Variable lease cost	588	898	1,155	1,690
Amortization	39	63	77	119
Interest on lease liabilities	4	4	7	7
Total lease cost	$ 10,376	$ 10,874	20,809	20,834
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases			11,953	18,440
Operating cash flows from finance leases			7	7
Financing cash flows from finance leases			69	113
Right-of-use assets obtained in exchange for lease obligations:
Operating leases			9,076	13,061
Finance leases			$ 60	$ 123