Stock-Based Compensation (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Non Qualified Stock Option [Member]
Stock Based Compensation [Line Items]
Outstanding at December 31, 2012, Number of options			624,700
Granted, Number of options	54,500	157,500	0
Exercised, Number of options			(49,600)
Forfeited, Number of options			(4,300)
Expired, Number of options			(1,500)
Outstanding at December 31, 2013, Number of options			569,300
Stock options expected to vest, Number of options			550,600
Exercisable at December 31, 2013, Number of options			268,200
Outstanding at December 31, 2012, Weighted average exercise price			$ 9.54
Granted, Weighted average exercise price			$ 0
Exercised, Weighted average exercise price			$ 10.46
Forfeited, Weighted average exercise price			$ 14.61
Expired, Weighted average exercise price			$ 13.17
Outstanding at December 31, 2013, Weighted average exercise price			$ 9.41
Stock options expected to vest, Weighted average exercise price			$ 9.39
Exercisable at December 31, 2013, Weighted average exercise price	$ 17.57	$ 13.18	$ 8.57
Outstanding at December 31, 2013, Weighted average remaining contractual term			2 years 5 months 12 days
Stock options expected to vest, Weighted average remaining contractual term			2 years 5 months 8 days
Exercisable at December 31, 2013, Weighted average remaining contractual term			2 years 3 months 7 days
Outstanding at December 31, 2013, Aggregate intrinsic value			$ 11,603,000
Stock options expected to vest, Aggregate intrinsic value			11,230,000
Exercisable at December 31, 2013, Aggregate intrinsic value			$ 5,691,000