Leases - Components of Lease Expense (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	$ 22,411	$ 26,506	$ 45,415	$ 53,648
Financing lease cost:
Amortization of right-of-use assets	426	291	903	577
Interest on lease liabilities	23	15	49	32
Total finance lease cost	449	306	952	609
Variable lease cost	9,833	9,876	19,310	19,749
Sublease income	(9,626)	(13,988)	(19,241)	(28,451)
Net lease cost	$ 23,067	$ 22,700	$ 46,436	$ 45,555