Stockholders' Equity (Schedule of Stock-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	$ 14,043	$ 10,817	$ 10,839
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	974	1,412	2,325
Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	7,023	4,343	5,425
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	1,031	910	911
Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	$ 5,015	$ 4,152	$ 2,178