Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Fair Value Assumptions for Stock Options

The following are the weighted-average assumptions used to calculate the grant-date fair values of stock option awards granted in the years ended December 31, 2018, 2017 and 2016:

	For the Years Ended December 31
	2018	2017	2016
Expected dividend yield	1.34%	1.39%	1.45%
Expected volatility	27.41%	30.01%	35.62%
Expected term	7.3 years	7.2 years	7.3 years
Risk-free interest rate	2.88%	2.22%	1.52%

Summary of Stock Option Activity

A summary of stock option activity for the year ended December 31, 2018 is presented below:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate IntrinsicValue ($000)
Options
Outstanding at January 1, 2018		391,805		$	52.09
Granted		77,038			73.08
Exercised		(97,471	)		42.71
Forfeited		(9,829	)		61.79
Outstanding at December 31, 2018		361,543			58.83		6.73	$	5,485
Vested or expected to vest at December 31, 2018		352,436			58.38		6.68		5,506
Exercisable at December 31, 2018		268,545			53.17		6.05		5,592

Summary of Stock Award Activity

A summary of stock award activity for the year ended December 31, 2018, is presented below:

	Shares			Weighted-Average Grant Date Fair Value
Stock Awards
Unvested at January 1, 2018		169,033		$	49.48
Granted		54,055			72.06
Vested		(119,501	)		41.88
Forfeited		(18,217	)		53.05
Unvested at December 31, 2018		85,370			73.65

Summary of SARs Activity

The following is a summary of SARs activity for the year ended December 31, 2018:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value ($000)
SARs
Outstanding at January 1, 2018		616,650		$	55.23
Granted		171,131			73.11
Exercised		(117,942	)		49.68
Forfeited		(30,693	)		63.66
Outstanding at December 31, 2018		639,146			60.64		7.10	$	8,430