Commitments and Contingencies (Schedule of Operating Lease Commitments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	$ 25,773
2019	21,193
2020	16,273
2021	11,557
2022	7,691
Thereafter	15,300
Total	97,787
Lease expense	$ 28,000	$ 27,300	$ 26,400
Office Space, Warehouses, Land and Buildings | Minimum
Operating Leased Assets [Line Items]
Operating lease, term	3 years
Office Space, Warehouses, Land and Buildings | Maximum
Operating Leased Assets [Line Items]
Operating lease, term	5 years
Machinery and Equipment | Minimum
Operating Leased Assets [Line Items]
Operating lease, term	1 year
Machinery and Equipment | Maximum
Operating Leased Assets [Line Items]
Operating lease, term	5 years