Acquisitions, Goodwill And Other Intangible Assets (Summary of Estimated Amortization Expense) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets
Amortization expense	$ 19,573	$ 17,758	$ 16,055
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity
2017	19,300
2018	17,352
2019	14,578
2020	12,918
2021	11,397
Cost of Sales
Finite-Lived Intangible Assets
Amortization expense	5,631	5,967	6,017
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity
2017	5,324
2018	4,680
2019	3,633
2020	3,093
2021	2,229
Selling, General and Administrative Expenses
Finite-Lived Intangible Assets
Amortization expense	13,942	$ 11,791	$ 10,038
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity
2017	13,976
2018	12,672
2019	10,945
2020	9,825
2021	$ 9,168