Leases - Components of Lease Cost (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 7,022	$ 22,520
Short-term lease cost	234	674
Sublease income	(681)	(2,128)
Total lease costs	$ 6,575	$ 21,066
Weighted-average remaining lease term (years)	5 years 8 months 12 days	5 years 8 months 12 days
Weighted-average discount rate	4.20%	4.20%
Cash paid for amounts included in the measurement of lease liabilities		$ 24,982
Right-of-use assets obtained in exchange for operating lease liabilities		4,082
Leasehold Improvements Reimbursed By Lessors As Lease Incentives		$ 2,156