Stock-Based Compensation (Options) (Details) - Stock Options [Member] $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Number of Shares
Options outstanding, beginning balance (in shares) | shares	1,826,210
Options exercised (in shares) | shares	(251,214)
Options outstanding, ending balance (in shares) | shares	1,575,000
Options vested and expected to vest, outstanding (in shares) | shares	1,570,560
Options exercisable, end of period (in shares) | shares	1,495,456
Weighted-Average Exercise Price
Options outstanding, beginning balance (usd per share) | $ / shares	$ 21.33
Options exercised (usd per share) | $ / shares	22.03
Options outstanding, ending balance (usd per share) | $ / shares	21.22
Options vested and expected to vest (usd per share) | $ / shares	21.20
Options exercisable, end of period (usd per share) | $ / shares	$ 20.68
Aggregate Intrinsic Value
Options outstanding, Aggregate Intrinsic Value | $	$ 27,152
Options vested and expected to vest, Aggregate Intrinsic Value | $	27,136
Options exercisable, Aggregate Intrinsic Value | $	$ 26,618
Weighted Average Remaining Contractual Term
Options outstanding, Weighted Average Remaining Contractual Term (in years)	5 years 15 days
Options vested and expected to vest, Weighted Average Remaining Contractual Term (in years)	5 years 15 days
Option exercisable, Weighted Average Remaining Contractual Term (in years)	4 years 10 months 28 days