Share-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Share-based Compensation [Abstract]

Assumptions to Estimate Fair Value of Option Grant on Date of Grant Using Black Scholes Option Pricing Model

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:

	Nine months ended September 30,
	2016			2015
Dividend yield	1.70		%	1.60		%
Volatility - stock option plans	24 - 25%			29 - 34%
Volatility - stock purchase rights plans	20		%	20		%
Risk free interest rates	0.51 - 1.42%			0.30 - 2.04%
Expected life (years) - stock option plans	5.50 - 6.50			6.41 - 7.47
Expected life (years) - stock purchase rights plans	1			1
Weighted average fair value of stock options granted during the period	$	9.57		$	13.44
Weighted average fair value of stock purchase rights granted during the period	$	10.99		$	10.45

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				Nine months ended
	September 30,				September 30,
	2016		2015		2016		2015
Stock compensation expense	$	10,476	$	10,919	$	34,264	$	32,489
Recognized tax benefit	$	2,149	$	1,571	$	5,928	$	4,305