Stock-Based Compensation (Options) (Details) - Stock Options [Member] $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Number of Shares
Options outstanding, beginning balance (in shares) | shares	1,504
Options exercised (in shares) | shares	(195)
Options outstanding, ending balance (in shares) | shares	1,309
Options vested and expected to vest, outstanding (in shares) | shares	1,309
Options exercisable, end of period (in shares) | shares	1,309
Weighted-Average Exercise Price
Options outstanding, beginning balance (usd per share) | $ / shares	$ 21.22
Options exercised (usd per share) | $ / shares	24.84
Options outstanding, ending balance (usd per share) | $ / shares	20.68
Options vested and expected to vest (usd per share) | $ / shares	20.68
Options exercisable, end of period (usd per share) | $ / shares	$ 20.68
Aggregate Intrinsic Value
Options outstanding, Aggregate Intrinsic Value | $	$ 29,724
Options vested and expected to vest, Aggregate Intrinsic Value | $	29,724
Options exercisable, Aggregate Intrinsic Value | $	$ 29,724
Weighted Average Remaining Contractual Term
Options outstanding, Weighted Average Remaining Contractual Term (in years)	2 years 11 months 20 days
Options vested and expected to vest, Weighted Average Remaining Contractual Term (in years)	2 years 11 months 20 days
Option exercisable, Weighted Average Remaining Contractual Term (in years)	2 years 11 months 20 days