Future Minimum Lease Payments under Operating and Capital Leases (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leases
2018	$ 6,695
2019	4,861
2020	3,121
2021	2,481
2022	605
Thereafter	6,449
Total minimum lease payments	24,212
Capital Leases
2018	1,013	[1]
2019	995	[1]
2020	983	[1]
2021	907	[1]
2022	907	[1]
Thereafter	6,325	[1]
Total minimum lease payments	$ 11,130	[1]

[1] Capital lease payments include interest payments of $2.7 million