Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Remaining lease terms	5 years	5 years	5 years
Operating lease cost	$ 3,822	$ 7,632
Sublease income	(875)	(1,685)
Net lease cost	$ 2,947	$ 5,947
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 year	1 year
Optional extension period		1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years	12 years
Optional extension period		5 years