Stock-Based Compensation (Options) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Aggregate Intrinsic Value
Options outstanding, Aggregate Intrinsic Value	$ 29,409
Options vested and expected to vest, Aggregate Intrinsic Value	29,348
Options exercisable, Aggregate Intrinsic Value	$ 27,419
Number of Shares
Options outstanding, beginning balance	2,562,000
Options granted		290,737
Options exercised	676,000
Options canceled	28,000
Options outstanding, ending balance	1,858,000
Options vested and expected to vest, outstanding	1,849,000
Options exercisable, end of period	1,604,000
Weighted Average Exercise Price
Options outstanding, Weighted Average Exercise Price, beginning balance	$ 22.32
Options exercised, Weighted Average Exercise Price	24.56
Options canceled, Weighted Average Exercise Price	29.27
Options outstanding, Weighted Average Exercise Price, ending balance	21.40
Options vested and expected to vest, Weighted Average Exercise Price	21.36
Options exercisable, Weighted Average Exercise Price, end of period	$ 20.14
Weighted Average Remaining Contractual Term
Options outstanding, Weighted Average Remaining Contractual Term (in years)	5 years 3 months 18 days
Options vested and expected to vest, Weighted Average Remaining Contractual Term (in years)	5 years 3 months 13 days
Option exercisable, Weighted Average Remaining Contractual Term (in years)	4 years 10 months 15 days