Employee Stock Plans (Stock Options) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, options granted (in dollars per share)	$ 5.03	$ 4.86	$ 3.55
Vested
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning balance (in shares)	4,688,256
Options granted (in shares)	569,523
Options exercised (in shares)	(776,293)
Options forfeited (in shares)	(402,860)
Options outstanding, ending balance (in shares)	4,078,626	4,688,256
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, beginning balance (in dollars per share)	$ 6.87
Weighted average exercise price, options granted (in dollars per share)	10.95
Weighted average exercise price, options exercised (in dollars per share)	5.31
Weighted average exercise price, options forfeited (in dollars per share)	9.19
Weighted average exercise price, ending balance (in dollars per share)	$ 7.51	$ 6.87
Non-Vested
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning balance (in shares)	1,862,787
Options granted (in shares)	569,523
Options vested (in shares)	(1,014,854)
Options forfeited (in shares)	(339,104)
Options outstanding, ending balance (in shares)	1,078,352	1,862,787
Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 3.62
Weighted average grant date fair value, options granted (in dollars per share)	5.03
Weighted average grant date fair value, options vested (in dollars per share)	3.59
Weighted average grant date fair value, options forfeited (in dollars per share)	3.75
Weighted average grant date fair value, ending balance (in dollars per share)	$ 4.34	$ 3.62