Share-Based Payment (Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Summary of stock option activity
Begining balance (shares)	803,617
Granted (shares)	45,783
Exercised (shares)	(72,794)	(24,500)
Canceled (shares)	(135,547)
Ending balance (shares)	641,059
Vested and expected to vest (shares)	628,171
Exercisable (shares)	423,110
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Beginning balance, weighted-average exercise price (dollars per share)	$ 20.83
Granted, weighted-average exercise price (dollars per share)	$ 28.97
Exercised, weighted-average exercise price (dollars per share)	$ 6.31
Canceled, weighted-average exercise price (dollars per share)	$ 12.26
Ending balance, weighted-average exercise price (dollars per share)	$ 21.66
Vested and expected to vest, weighted-average exercise price (dollars per share)	$ 21.63
Exercisable, weighted-average exercise price (dollars per share)	$ 21.90
Outstanding, weighted-average remaining contractual term (in years)	6 years 0 months 4 days
Vested and expected to vest, weighted-average remaining contractual term (in years)	6 years 0 months 7 days
Exercisable, weighted-average remaining contractual term (in years)	5 years 2 months 25 days
Outstanding, aggregate intrinsic value	$ 4,657
Vested and expected to vest, aggregate intrinsic value	4,604
Exercisable, aggregate intrinsic value	$ 3,475