Stock-Based Compensation (Options) (Details) - Stock Options [Member] $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares
Aggregate Intrinsic Value
Options outstanding, Aggregate Intrinsic Value | $	$ 22,358
Options vested and expected to vest, Aggregate Intrinsic Value | $	22,348
Options exercisable, Aggregate Intrinsic Value | $	$ 22,052
Number of Shares
Options outstanding, beginning balance | shares	1,826,210
Options exercised | shares	(165,495)
Options outstanding, ending balance | shares	1,661,000
Options vested and expected to vest, outstanding | shares	1,655,322
Options exercisable, end of period | shares	1,574,676
Weighted Average Exercise Price
Options outstanding, Weighted Average Exercise Price, beginning balance | $ / shares	$ 21.33
Options exercised, Weighted Average Exercise Price | $ / shares	22.42
Options outstanding, Weighted Average Exercise Price, ending balance | $ / shares	21.22
Options vested and expected to vest, Weighted Average Exercise Price | $ / shares	21.20
Options exercisable, Weighted Average Exercise Price, end of period | $ / shares	$ 20.70
Weighted Average Remaining Contractual Term
Options outstanding, Weighted Average Remaining Contractual Term (in years)	5 years 3 months 11 days
Options vested and expected to vest, Weighted Average Remaining Contractual Term (in years)	5 years 3 months 11 days
Option exercisable, Weighted Average Remaining Contractual Term (in years)	5 years 1 month 28 days