Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2011

Stockholders' Equity [Abstract]

Summary Of Nonvested Restricted Common Stock Transactions

	Shares of  restricted common stock and units			Weighted average grant  date fair value
Nonvested at December 31, 2010		820		$	19.66
Granted		265		$	24.45
Cancelled		(38	)	$	17.77
Vested		(279	)	$	21.88
Nonvested at December 31, 2011		768		$	20.47

Summary Of Stock Option Transactions Relating To Non-Qualified Stock Option Plans

	No. of options			Weighted- Average Exercise Price of options		Weighted -Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2010		3,495		$	16.95
Granted		575			24.45
Exercised		(268	)		7.97
Cancelled		(149	)		21.02
Outstanding at December 31, 2011		3,653		$	18.63		6.1	$	14,208
Exercisable at December 31, 2011		2,464		$	17.55		4.9	$	12,157

Schedule Of Estimated Fair Value Of Option Grant Using Black-Scholes Option Pricing Model

	2011			2010			2009
Expected dividend yield		0.0	%		0.0	%		0.0	%
Expected stock price volatility		42.1	%		38.8	%		36.4	%
Risk-free interest rate		2.1	%		2.4	%		1.8	%
Expected life of options		5 years			5 years			5 years

Summary Of Nonvested Stock Option Transactions Relating To Non-Qualified Stock Option Plans

	Number of options			Weighted average  grant date fair value
Nonvested at December 31, 2010		1,289		$	6.46
Granted		575		$	9.66
Cancelled		(106	)	$	6.86
Vested		(569	)	$	6.62
Nonvested at December 31, 2011		1,189		$	7.89