Leases - Lease Costs and Other Quantitative Information (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	$ 18,511	$ 17,473	$ 34,902	$ 33,914
Variable lease cost	3,573	4,361	8,228	9,325
Sublease rental income	(2,892)	(2,590)	(5,697)	(4,189)
Total lease cost	19,192	19,244	37,433	39,050
Operating cash flows	17,592	19,523	35,227	35,175
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 30,815	$ 2,195	$ 37,934	$ 259,013
Weighted average remaining lease term (in years) - Operating leases	7 years 4 months 24 days	7 years	7 years 4 months 24 days	7 years
Weighted average discount rate - Operating leases	1050.00%	860.00%	1050.00%	860.00%