Stock-Based Compensation (Table)

3 Months Ended

12 Months Ended

Mar. 31, 2012

Dec. 31, 2011

Stock-Based Compensation [Abstract]

Summary of ESPP share activity

	Shares
Available for future purchases, January 1, 2012		253,294
Purchases		43,091
Available for future purchases, March 31, 2012		210,203

	Shares
2009 ESPP Plan Shares available for future purchases, January 1, 2011		331,795
Additional Shares reserved under 2009 ESPP		77,928
Purchases		(156,429	)
Shares available for future purchases, December 31, 2011		253,294

Weighted average fair value of options granted

Grant Year	Dividend Yield			Expected Volatility			Risk Free Interest  Rate			Expected Lives
2011		0	%		52	%		2	%		5
2010		0	%		54	%		2	%		5
2009		0	%		55	%		2	%		5

Stock option transactions under various stock-based employee compensation plans

	Shares			Weighted Average Exercise Price		Weighted Average Contractual Life
Outstanding, beginning of year		2,828,770		$	20.85
Granted		68,000			33.28
Exercised		(113,359	)		17.62
Canceled		(80,782	)		21.62
Outstanding, end of year		2,702,629		$	21.27		7.07
Exercisable at end of year		1,500,656		$	22.86		6.78

Unvested stock options

	Shares			Weighted Average Grant Date Fair Value
Non-vested stock options at the beginning of the period		1,832,153		$	9.20
Granted		54,400			9.33
Vested		(623,362	)		9.49
Canceled		(61,218	)		9.14
Non-vested stock options at the end of the period		1,201,973		$	9.06