Share-Based Compensation and Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2015

Stock Option [Member]

Summary of stock options

	Shares (in thousands)		Weighted-Average Exercise Price
Outstanding at December 31, 2014	4,065		$	64.57
Granted	267		205.14
Exercised	(591	)	51.46
Forfeited	(59	)	87.44
Outstanding at June 30, 2015	3,682		$	76.50
Exercisable at June 30, 2015	2,476		$	49.27

Black-Scholes option pricing model

	For the Six Months Ended   June 30,
	2015		2014
Risk free interest rate	1.55	%	1.65	%
Expected life	5.9 Years		5.5 Years
Expected volatility	22.4	%	25.2	%
Expected dividend yield	—	%	—	%

Summary of activity of share-based compensation

	For the Three Months Ended   June 30,				For the Six Months Ended   June 30,
	2015		2014		2015		2014
Compensation expense for stock options awarded	$	4,510	$	5,710	$	9,507	$	9,794
Income tax benefit from compensation expense related to stock options	1,694		2,113		3,541		3,625

Restricted Stock [Member] | Employee Stock Purchase Plan [Member]

Summary of activity of share-based compensation

	For the Three Months Ended   June 30,				For the Six Months Ended   June 30,
	2015		2014		2015		2014
Compensation expense for shares issued under the ESPP	$	497	$	443	$	987	$	881
Income tax benefit from compensation expense related to shares issued under the ESPP	187		164		368		326
Compensation expense for restricted shares awarded	407		889		810		1,462
Income tax benefit from compensation expense related to restricted awards	$	153	$	329	$	302	$	541