Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2012

Share-based Compensation [Abstract]

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:

	Six months ended June 30,
	2012			2011
Dividend yield	1.30		%	0.97		%
Volatility - stock option plans	38 - 39 %			38 - 40%
Risk free interest rates	0.89 - 1.43%			2.17 - 2.84%
Expected life (years) - stock option plans	5.79 - 7.26			5.50 - 7.11
Weighted average fair value of stock options granted during the period	$	13.53		$	19.35

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

Total stock compensation expense and the total related tax benefit recognized are as follows:

	Three months ended				Six months ended
	June 30,				June 30,
	2012		2011		2012		2011
Stock compensation expense	$	10,926	$	10,236	$	21,526	$	20,708
Recognized tax benefit	$	336	$	39	$	375	$	77