Leases Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lease, Cost [Abstract]
Fixed costs	$ 8,950	$ 8,347	$ 26,027	$ 25,183
Variable costs	15	7	40	77
Short-term lease costs	117	126	312	849
Sublease income	(1,081)	(1,010)	(3,100)	(3,190)
Net lease expense	$ 8,001	$ 7,470	23,279	22,919
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases			25,198	24,674
ROU assets obtained in exchange for lease obligations:
Operating leases			$ 19,027	$ 172,189