Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Share-Based Compensation [Abstract]

Stock Option Activity

The following is a summary of the stock option activity under our share-based plans for the year ended December 31, 2011:

	Shares			Weighted Average Exercise Price	Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Balance at December 31, 2010	5,255,165		$	22.08
Granted	404,500			24.50
Exercised	(958,509	)		12.70
Forfeited	(31,919	)		19.30
Balance at December 31, 2011	4,669,237		$	24.23	5.07	$	35,441,126
Exercisable at December 31, 2011	2,595,660		$	25.44	3.23	$	18,372,236

Stock options outstanding and exercisable by exercise price range

The table below summarizes information about stock options outstanding and exercisable at December 31, 2011:

	Outstanding Stock Options				Exercisable Stock Options
		Weighted Average
		Remaining	Weighted			Weighted
		Contractual Term	Average			Average
Range of exercise prices	Shares	(Years)	Exercise Price		Shares	Exercise Price
$ 0.00 to $ 11.99	449,960	1.12	$	11.98	449,960	$	11.98
$ 12.00 to $ 17.99	166,696	0.31		13.38	166,696		13.38
$ 18.00 to $ 23.99	2,219,973	6.08		20.17	803,184		21.09
$ 24.00 to $ 29.99	451,966	8.61		24.69	49,466		26.21
$ 30.00 to $ 47.30	1,380,642	4.14		35.92	1,126,354		35.66
	4,669,237	5.07	$	24.23	2,595,660	$	25.44

Summary of cash proceeds and tax benefits realized from stock option exercise.

The following table summarizes the cash proceeds and tax benefits realized from the exercise of stock options:

		Year Ended December 31,
(in thousands, except share amounts)		2011		2010		2009
Options exercised		958,509		650,210		557,252
Cash proceeds	$	12,173	$	5,411	$	3,439
Intrinsic value of options exercised	$	13,868	$	8,589	$	7,870
Tax benefits realized	$	5,409	$	3,375	$	3,093

Summary of assumptions for estimated fair value of employee stock option awards at grant date

We estimated the fair value of employee stock option awards at the grant date based on the assumptions summarized in the following table:

		Year Ended December 31,
(Weighted average)		2011			2010			2009
Expected volatility		37.9	%		38.9	%		36.6	%
Expected term		7.8	years		6.7	years		6.7	years
Risk-free interest rate		3.10	%		3.23	%		2.94	%
Expected dividend yield		2.0	%		2.0	%		2.0	%
Grant date fair value	$	8.97		$	7.34		$	6.18

Summary of share-based compensation expense and recognized tax benefits

The table below presents the total share-based compensation expense for stock option awards and the related recognized tax benefits for the past three years (in thousands):

		2011		2010		2009
Share-based compensation expense	$	4,497	$	4,570	$	4,681
Recognized tax benefits		1,721		1,796		1,840

The table below presents the total share-based compensation expense for restricted stock awards for the past three years (in thousands):

		2011		2010		2009
Share-based compensation expense	$	3,507	$	3,028	$	1,560

Summary of restricted stock award activity

The following is a summary of the restricted stock awards activity under our share-based plans for the year ended December 31, 2011:

	Shares		Weighted Average Grant Date Fair Value
Balance unvested at December 31, 2010	418,621		$	21.49
Granted (at market price)	126,725			25.74
Vested	(32,856	)		24.71
Forfeited	(7,200	)		19.66
Balance unvested at December 31, 2011	505,290		$	22.37

Total restricted stock awards that vested for the past three years and related fair value

The table below presents the total number of restricted stock awards that vested for the past three years and the related fair value of those awards (in thousands, except share amounts):

		2011		2010		2009
Shares vested		32,856		44,152		58,748
Fair value of restricted stock awards vested	$	812	$	1,077	$	1,010

Number of shares purchased by employees under the employee stock purchase plan

For the two six month offering periods in each year presented below, our employees purchased the following aggregate number of shares:

2011	2010	2009
37,653	48,002	57,839