Commitments and Contingencies (Minimum Rentals) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
Long-term debt maturities, 2018	$ 14,500
Long-term debt maturities, 2019	14,500
Long-term debt maturities, 2020	14,500
Long-term debt maturities, 2021	356,779
Long-term debt maturities, 2022	0
Long-term debt maturities, Thereafter	0
Total Debt	400,279
Less: current portion	(14,500)
Long-term obligations, Debt	385,779
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital Leases, future minimum payments due, 2018	20
Capital Leases, future minimum payments due, 2019	20
Capital Leases, future minimum payments due, 2020	8
Capital Leases, future minimum payments due, 2021	0
Capital Leases, future minimum payments due, 2022	0
Capital Leases, future minimum payments due, Thereafter	0
Total capital lease obligations	48
Less: amount representing interest	(5)
Present value of obligations under capital leases	43
Less: current portion	(17)
Long-term obligations, Capital Leases	26
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, future minimum payments due, 2018	6,937
Operating Leases, future minimum payments due, 2019	4,835
Operating Leases, future minimum payments due, 2020	3,015
Operating Leases, future minimum payments due, 2021	1,847
Operating Leases, future minimum payments due, 2022	1,209
Operating Leases, future minimum payments due, Thereafter	1,828
Total operating lease obligations	19,671
Less: sublease income	(2,215)
Net lease payments	17,456
Purchase Obligation, Fiscal Year Maturity [Abstract]
Purchase Obligation,future minimum payments due, 2018	541
Purchase Obligation,future minimum payments due, 2019	406
Purchase Obligation, future minimum payments due, 2020	0
Purchase Obligation, future minimum payments due, 2021	0
Purchase Obligation, future minimum payments due, 2022	0
Purchase Obligation, future minimum payments due, Thereafter	0
Total Purchase Obligation	$ 947