Leases Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lease, Cost [Abstract]
Fixed costs	$ 8,832	$ 8,534	$ 17,077	$ 16,836
Variable costs	12	46	25	70
Short-term lease costs	102	203	194	723
Sublease income	(1,003)	(1,054)	(2,019)	(2,180)
Net lease expense	$ 7,943	$ 7,729	15,277	15,449
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases			16,519	16,408
ROU assets obtained in exchange for lease obligations:
Operating leases			$ 14,542	$ 149,621