Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases, Operating [Abstract]
Carrying value of operating lease equipment after depreciation	$ 134,440	$ 139,581
Accumulated depreciation	65,510	49,740
Minimum future lease rental payments due from clients
Total	99,890
2019	30,540
2020	32,830
2021	18,680
2022	10,760
2023	5,290
Thereafter	1,790
Depreciation expense related to operating lease equipment	$ 26,248	$ 25,215	$ 21,678