Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

The following table summarizes the Company’s stock option activity and related information for the 2011 Plan, the 2000 Plan and the Directors Plan for the three months ended March 31, 2016:



	Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life	Aggregate Intrinsic value (in thousands)
Outstanding at December 31, 2015	1,097,323		$	32.70	4.8	$	42,154
Granted	93,765		61.33			1,779
Exercised	(21,565	)	23.90			1,216
Canceled	(4,471	)	68.03			55
Outstanding at March 31, 2016	1,165,052		35.04		5.0	52,735
Exercisable at March 31, 2016	942,015		27.17		4.2	50,051

Share-Based Fair Value of Each Option Grant Weighted-Average Assumptions

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



	Three Months Ended March 31,
	2016		2015
Dividend yield	0.26	%	0.14	%
Risk-free interest rate	1.47	%	1.82	%
Stock price volatility	26.9	%	27.3	%
Expected life (years)	5.0		5.0

Restricted Stock Activity and Incentive Stock Awards Activity

The following table summarizes the restricted stock activity and related information for the 2011 Plan, the 2000 Plan and the Directors Plan, and incentive stock units activity for the 2011 Plan and the 2000 Plan with related information for the three months ended March 31, 2016:



	Restricted Stock and Units		Incentive Stock Awards		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2015	356,885		541,638		$	65.89
Granted	128,565		167,350		61.33
Vested	(130,083	)	(236,951	)	50.89
Adjustment for incentive stock awards expected to vest	—		(622	)	75.66
Canceled	(6,158	)	(3,733	)	69.66
Outstanding at March 31, 2016	349,209		467,682		70.90