Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Lease expiration date	Mar. 31, 2028
Rent expense	$ 23,348	$ 21,566	$ 18,640
Minimum rentals for aggregate lease commitments
2019	15,200
2020	8,973
2021	5,535
2022	3,592
2023	2,636
Thereafter	4,215
Total	40,151
Aggregate residual value at lease expiration for vehicle leases	14,043
Guaranteed aggregate residual value at lease expiration for vehicle leases	8,404
Liability for the estimated end-of-term loss related to residual value guarantee	$ 243
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	5360