Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following table summarizes the assumptions used in estimating the fair value of these awards:

Grant Date	Stock Price on Measurement Date		Expected Volatility		Risk Free Interest Rate		Expected Term	Weighted Avg. Grant Date Fair Value
2017	$	127.51	24.7	%	1.9	%	3 Years	$	119.88
2016	$	113.69	25.6	%	1.4	%	3 Years	$	104.93
2015	$	97.48	23.3	%	1.3	%	3 Years	$	87.61

Schedule of Activity Related to Employee and Non-Employee Restricted Stock

Activity related to both employee and non-employee restricted stock for the year ended December 31, 2017 is as follows (in thousands, except per share amounts):

	Shares		Weighted Average Grant Date Fair Value/Share
RESTRICTED STOCK AT DECEMBER 31, 2016	224		$	102.37
Shares granted	81		123.39
Shares vested	(62	)	106.06
Shares forfeited	(4	)	104.54
RESTRICTED STOCK AT DECEMBER 31, 2017	239		$	108.51

Summary of Stock Appreciation Rights

Activity related to SARs for the year ended December 31, 2017 is as follows (in thousands, except per share amounts):

	Number of Rights		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
OUTSTANDING AT DECEMBER 31, 2016	1,811		$	94.51
Granted	432		127.28
Exercised	(191	)	70.78
Forfeited	(9	)	107.39
Canceled	(1	)	97.48
OUTSTANDING AT DECEMBER 31, 2017	2,042		$	103.59	7.4 Years	$	64,841
EXERCISABLE AT DECEMBER 31, 2017	1,241		$	93.89	6.2 Years	$	51,420

Summary of the Weighted-Average Assumption Used in Estimating Fair Value of Stock Appreciation Rights

The following table summarizes the weighted-average assumptions used in estimating the fair value of the SARs granted during the years 2017, 2016 and 2015:

Grant Date	Expected Dividend Yield		Expected Volatility		Risk Free Interest Rate		Expected Term	Weighted Avg. Grant Date Fair Value of 1 SAR
2017	2.6	%	18.0	%	2.2	%	5.5 Years	$	17.45
2016	2.6	%	22.3	%	1.9	%	5.5 Years	$	18.76
2015	2.7	%	22.7	%	1.7	%	5.5 Years	$	16.05

Summary of Performance Shares Valuation

The following table summarizes the related assumptions used to determine the fair values of the performance share awards with a market condition granted during the years 2017, 2016 and 2015:

Grant Date	Stock Price on Measurement Date		Dividend Yield		Expected Volatility		Risk Free Interest Rate		Expected Term	Weighted Avg. Grant Date Fair Value
2017	$	127.51	2.4	%	24.7	%	1.9	%	3 Years	$	142.89
2016	$	113.69	2.5	%	25.6	%	1.4	%	3 Years	$	126.65
2015	$	97.48	2.6	%	23.3	%	1.3	%	3 Years	$	105.77

Summary of the Attributes of the Performance Shares Granted During the Period

The following table summarizes the attributes of the performance shares outstanding at December 31, 2017:

Grant Date	Shares Outstanding at 12/31/2017	Fair Value	Performance Period	Payout Range
2017	24,675	118.55	Jan 2018-Dec 2020	0-250%
2016	28,524	105.48	Jan 2017-Dec 2019	0-250%
2015	31,024	97.48	Jan 2016-Dec 2018	0-250%
2014	23,688	106.44	Jan 2015-Dec 2017	0-250%