Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense	$ 11,120,000	$ 8,878,000	$ 7,833,000
Income tax benefits	(3,874,000)	(3,102,000)	(2,724,000)
Total stock-based compensation expense, net of tax	7,246,000	5,776,000	5,109,000
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense	399,000	347,000	287,000
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense	$ 10,721,000	$ 8,531,000	$ 7,546,000