Share-Based Compensation and Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2016

Restricted stock [Member]

Share-Based Compensation and Benefit Plans

Summary of activity of share-based compensation

	For the Three Months Ended   September 30,				For the Nine Months Ended   September 30,
	2016		2015		2016		2015
Compensation expense for shares issued under the ESPP	$	538	$	526	$	1,610	$	1,513
Income tax benefit from compensation expense related to shares issued under the ESPP	201		198		601		565
Compensation expense for restricted shares awarded	327		417		968		1,227
Income tax benefit from compensation expense related to restricted awards	$	122	$	157	$	361	$	459

Stock option [Member]

Share-Based Compensation and Benefit Plans

Summary of stock options

	Shares		Weighted-Average Exercise Price
Outstanding at December 31, 2015	3,308		$	80.86
Granted	289		266.64
Exercised	(620	)	61.77
Forfeited	(54	)	139.76
Outstanding at September 30, 2016	2,923		$	102.18
Exercisable at September 30, 2016	2,087		$	62.77

Black-Scholes option pricing model

	For the Nine Months Ended   September 30,
	2016		2015
Risk free interest rate	1.45	%	1.54	%
Expected life	5.6 Years		5.8 Years
Expected volatility	22.4	%	22.3	%
Expected dividend yield	—	%	—	%

Summary of activity of share-based compensation

	For the Three Months Ended   September 30,				For the Nine Months Ended   September 30,
	2016		2015		2016		2015
Compensation expense for stock options awarded	$	3,653	$	4,409	$	11,793	$	13,916
Income tax benefit from compensation expense related to stock options	1,365		1,657		4,405		5,198