Leases - Future Minimum Rental Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Future minimum rental payments under noncancelable leases
2019 (excluding the three months ended March 31, 2019)	$ 7,040
2020	8,691
2021	7,984
2022	5,125
2023	2,632
Thereafter	34,638
Total future minimum lease payments	66,110
Less: Imputed interest	(17,172)
Total	$ 48,938
Future minimum rental payments in accordance with ASC Topic 840, Leases
2019		$ 8,780
2020		8,668
2021		7,961
2022		5,101
2023		2,632
Thereafter		34,638
Total future minimum lease payments		67,780
Less Sublease Income
2019		903
2020		903
2021		892
Total future minimum lease payments		2,698
Net Operating Lease Payments
2019		7,877
2020		7,765
2021		7,069
2022		5,101
2023		2,632
Thereafter		34,638
Total future minimum lease payments		$ 65,082