Leases - Components of Lease Cost (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 7,414	$ 15,498
Short-term lease cost	207	440
Sublease income	(725)	(1,447)
Total lease costs	$ 6,896	$ 14,491
Weighted-average remaining lease term (years)	5 years 8 months 12 days	5 years 8 months 12 days
Weighted-average discount rate	4.25%	4.25%
Cash paid for amounts included in the measurement of lease liabilities		$ 14,345
Right-of-use assets obtained in exchange for operating lease liabilities		2,298
Leasehold Improvements Reimbursed By Lessors As Lease Incentives		$ 1,738