Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2012

Stock-Based Compensation [Abstract]

Schedule Of Option Activity And Changes

	Options			Weighted Average Exercise Price		Weighted Average Remaining Term (Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2011		1,133,147		$	23.26
Granted		115,340			60.09
Exercised		(19,430	)		24.75
Cancelled		—			—
Outstanding at March 31, 2012		1,229,057		$	26.70		6.6	$	46,820
Exercisable at March 31, 2012		850,834		$	20.64		6.0	$	37,570

Schedule Of Range Of Exercise Prices For Outstanding Options

Range of Prices	Options Outstanding		Weighted Average Remaining Contractual Life (Years)
$14.24—$19.29		498,745		5.9
$20.53—$27.24		253,746		7.3
$30.07—$36.10		264,200		4.8
$45.83—$60.11		212,366		9.4

Schedule Of Weighted Average Value And Assumptions For Fair Value Of Options

	Stock Option Grants
	Three Months Ended March  31,
	2012			2011
Weighted average fair value	$	23.39		$	19.22
Risk-free interest rate		1.0	%		2.8	%
Expected life in years		5			6
Expected volatility		45.7	%		41.9	%
Expected dividend yield		0.5	%		0.5	%

Schedule Of Non-Vested Restricted Stock Award Activity And Changes

	Number of Shares			Weighted Average Grant Date Fair Value
Non-vested at December 31, 2011		582,013		$	23.43
Granted		68,715			60.11
Vested		(298,151	)		17.51
Forfeited		(2,060	)		27.64
Non-vested at March 31, 2012		350,517		$	35.64