Summary of Significant Accounting Policies (Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Share-based compensation expense	$ 29,451	$ 28,334	$ 29,930
Tax benefit recognized for share-based compensation arrangements	11,500	10,900	11,600
Excess tax benefit on share-based compensation	$ 4,855	$ 2,230	$ 620