Employee Benefit Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based awards issued	5,800,000
Share-based awards available for grant	2,300,000
Share-based compensation expense	$ 1,800,000	$ 2,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 years
Options Outstanding [Roll Forward]
Unamortized compensation costs	13,000,000
Options - Additional Disclosures [Abstract]
Proceeds from Stock Options Exercised	962,000	612,000
Unvested Shares [Roll Forward]
Unvested shares at March 31, 2013 (shares)	317,198
Stock Options
Options Outstanding [Roll Forward]
Options outstanding at January 1, 2013	5,519,345
Options outstanding at January 1, 2013, weighted average exercise price, beginning balance	$ 11.78
Options granted, shares	67,000
Options granted, weighted average exercise price	$ 15.58
Options exercised, shares	(96,159)
Options exercised, weighted average exercise price	$ 9.98
Options cancelled or forfeited, shares	(44,550)
Options cancelled or forfeited, weighted average exercise price	$ 12.94
Options outstanding at March 31, 2013	5,445,636
Options outstanding, weighted average exercise price, ending balance	$ 11.85
Options Vested and Expected to Vest [Abstract]
Expected to vest at a point in the future as of March 31, 2013	2,019,114
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 10.99
Options - Additional Disclosures [Abstract]
Options exercisable at March 31, 2013, shares	2,780,461
Options exercisable at March 31, 2012, weighted average exercise price	$ 12.68
Weighted-average value per granted option calculated using the Black-Scholes option-pricing model for options granted during the three months ended March 31, 2013	$ 7.82	$ 5.67
Non-vested Stock [Member]
Options Outstanding [Roll Forward]
Unamortized compensation costs	$ 3,400,000
Unvested Shares [Roll Forward]
Unvested shares at January 1, 2013 (shares)	220,537
Unvested shares at January 1, 2013 (Weighted-avereage grant date fair value)	$ 11.33
Unvested shares granted (shares)	128,092
Unvested shares ganted (Weighted-avereage grant date fair value)	$ 14.34
Unvested shares vested (shares)	(31,431)
Unvested shares granted (Weighted-avereage grant date fair value)	$ 13.56
Unvested shares cancelled/forfeited (shares)	0
Unvested shares cancelled/forfeited (Weighted-avereage grant date fair value)	$ 0.00
Unvested shares at March 31, 2013 (Weighted-avereage grant date fair value) CLONE	$ 12.33
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based awards issued	300,000