Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Schedule of share-based compensation expenses

Total share-based compensation expenses were as follows (in thousands):

	For the Years Ended December 31,
	2017		2016		2015
Option plan	$	18,423	$	23,876	$	26,191
Other share-based awards	28,844		23,368		23,275
Total share-based compensation before tax	47,267		47,244		49,466
Tax benefit	17,555		17,546		18,451
Total share-based compensation expense included in net income	$	29,712	$	29,698	$	31,015

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

The following summarizes stock option activity and the weighted average exercise price for the following plans for the each of the three years ended December 31, 2017, 2016 and 2015:

	Omnibus Plan (Active)				Option Plan (Frozen)
	Outstanding Shares		Weighted Average Exercise Price		Outstanding Shares		Weighted Average Exercise Price
Balance as of December 31, 2014	4,206,512		$	66.38	63,233		$	23.76
Granted	743,062		150.81		—		—
Exercised	(706,750	)	40.21		(44,283	)	23.92
Forfeited	(137,285	)	112.95		—		—
Balance as of December 31, 2015	4,105,539		$	84.61	18,950		$	23.37
Granted	1,326,430		78.72		—		—
Exercised	(348,206	)	40.51		(18,950	)	23.37
Forfeited	(366,702	)	108.90		—		—
Balance as of December 31, 2016	4,717,061		$	84.32	—		—
Granted	1,267,812		88.22		—		—
Exercised	(898,417	)	44.18		—		—
Forfeited	(192,505	)	108.15		—		—
Balance as of December 31, 2017	4,893,951		$	91.78	—		—
Vested or expected to vest as of December 31, 2017	4,893,951		$	91.78	—		—
Options exercisable as of December 31, 2017	1,921,189		$	88.21	—		—

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The following assumptions were used to estimate the weighted average fair value of options of $18.45, $16.81 and $37.64 granted during the years ended December 31, 2017, 2016 and 2015, respectively:

	For the Years Ended December 31,
	2017		2016		2015
Weighted-average volatility	29	%	32	%	32	%
Expected dividend yield	2.6	%	2.8	%	1.4	%
Expected term (in years)	4.7		4.5		4.5
Weighted average risk free interest rate	1.9	%	1.4	%	1.5	%

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table summarizes restricted stock activity for the year ended December 31, 2017:

	Shares Outstanding		Weighted Average Grant Price
Balance as of December 31, 2016	1,521,202		$	103.05
Granted	526,119		85.97
Vested	(84,663	)	134.23
Canceled/Forfeited	(342,033	)	116.55
Balance as of December 31, 2017	1,620,625		$	93.03
Expected to vest as of December 31, 2017	1,176,085		$	87.92