Stock Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2012

Stock Incentive Plans [Abstract]

Summary of activity of stock incentive and equity plans

	Shares available for grant			Number of options outstanding			Weighted- average option exercise price		Number of restricted stock and board shares issued
Outstanding at December 31, 2009		874,269			2,194,286		$	9.48		34,863
Granted		(238,826	)		238,826			27.54		—
Exercised		—			(594,308	)		5.86		—
Canceled/forfeited		8,407			(8,407	)		16.63		—
Outstanding at December 31, 2010		643,850			1,830,397			12.98		34,863
Authorized		2,100,000			—			—		—
Granted		(389,774	)		382,050			16.02		7,724
Exercised		—			(73,428	)		10.78		—
Expired		(139,988	)		—			—		—
Canceled/forfeited		45,911			(45,911	)		20.15		—
Outstanding at December 31, 2011		2,259,999			2,093,108			13.45		42,587
Granted		(106,395	)		89,050			9.72		17,345
Exercised		—			(17,885	)		4.01		—
Canceled/forfeited		47,000			(47,163	)		15.13		—
Outstanding at December 31, 2012		2,200,604			2,117,110		$	13.32		59,932

Intrinsic value calculated based on grant date fair value

Date of Grant	Number of options granted		Exercise price		Intrinsic value per share
February 2010		7,500		15.00		—
March - April 2010		50,671		19.49 - 20.20		—
June - August 2010		145,655		24.95 - 32.67		—
October 2010		35,000		22.69		—
January 2011		26,000		18.80 - 21.64		—
March - April 2011		73,500		25.61 - 27.63		—
May 2011		51,650		22.92		—
July 2011		12,500		16,86		—
October 2011		75,400		10.81 - 10.93		—
December 2011		143,000		10.19		—
January 2012		8,500		9.39		—
April-May 2012		36,750		9.45 - 10.43		—
July 2012		7,000		10.20		—
September- October 2012		36,800		9.41 - 9.58		—

Exercise prices of outstanding options

Exercise Price	Number of options outstanding		Average remaining contractual life (years)		Number of options exercisable
$0.78 - $4.94		561,170		5.01		400,767
7.75 - 9.58		322,989		7.85		266,114
10.02 - 14.00		386,617		8.55		199,830
14.57 - 18.80		75,854		7.11		61,604
19.21 - 22.92		557,625		7.74		277,438
24.95 - 32.67		212,855		7.58		90,355
		2,117,110		7.18		1,296,108

Summary of the non-vested options

	Non-vested options			Weighted- Average Option Exercise price
Non-vested at December 31, 2009		1,500,640		$	10.22
Granted		238,826			27.54
Vested		(391,788	)		7.29
Cancelled		(8,292	)		16.70
Non-vested at December 31, 2010		1,339,386			14.12
Granted		382,050			16.02
Vested		(366,484	)		10.72
Cancelled		(41,775	)		20.39
Non-vested at December 31, 2011		1,313,177			13.58
Granted		89,050			9.72
Vested		(540,050	)		14.77
Cancelled		(41,175	)		15.38
Non-vested at December 31, 2012		821,002		$	15.24

Analysis of restricted stock issued

Non-vested restricted stock as of December 31, 2010	1,762
Granted	7,724
Vested	(7,555	)
Non-vested restricted stock as of December 31, 2011	1,931
Granted	17,345
Vested	(14,940	)
Non-vested restricted stock as of December 31, 2012	4,336