Stock Compensation Summary of stock option activity for the period (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at January 1, 2013	1,919,021
Options Granted (in shares)	323,400
Options Exercised, Shares (in shares)	(155,178)
Cancelled or Forfeited (in shares)	(127,320)
Outstanding at March 31, 2013 (in shares)	1,959,923
Exercisable at March 31, 2013 (in shares)	1,428,395
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at January 1, 2013 Average Price (in dollars per share)	$ 11.63
Options granted, average exercise price (in dollars per share)	$ 14.77
Options exercised, average exercise price (in dollars per share)	$ 10.82
Cancelled or forfeited, average exercise price (in dollars per share)	$ 13.91
Outstanding at March 31, 2013 Average Price (in dollars per share)	$ 12.07
Exercisable at March 31, 2013, Average Exercise Price (in dollars per share)	$ 11.55
Outstanding at March 31, 2013 Weighted Average Life	6 years 7 months 17 days
Exercisable at March 31, 2013, Weighted Average Life	5 years 7 months 24 days