Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Share-Based Compensation

Schedule of stock option activity

		Weighted			Weighted			Weighted
		Average			Average			Average
		Exercise			Exercise			Exercise
	Shares	Price		Shares	Price		Shares	Price
Outstanding at  January 1	285,405	$	38.85	294,342	$	35.91	295,916	$	33.26
Granted	25,682		63.79	26,430		61.74	22,497		65.59
Exercised	(63,527)		34.70	(35,360)		31.51	(22,878)		31.06
Forfeited	(1,025)		35.20	—		—	(1,180)		31.97
Expired	—		—	(7)		31.72	(13)		27.22
Outstanding at December 31	246,535		42.53	285,405		38.85	294,342		35.91
Exercisable at December 31	185,758		36.33	227,130		34.48	239,417		33.17
Weighted-average fair value of options granted during the year		$	25.19		$	25.08		$	26.44

Schedule of information pertaining to options outstanding

					Options Outstanding				Options Exercisable
						Weighted					Weighted
						Average					Average
						Remaining		Weighted		Weighted	Remaining
Range of					Number	Contractual		Average	Number	Average	Contractual
Exercise Prices					Outstanding	Life		Exercise Price	Outstanding	Exercise Price	Life
$	26.01	-	$	30.00	24,296	2.3	years	27.46	24,296	27.46
$	30.01	-	$	35.00	93,388	3.4	years	31.69	93,385	31.69
$	35.01	-	$	40.00	29,735	2.2	years	36.90	29,732	36.89
$	40.01	-	$	45.00	24,507	5.9	years	41.42	19,163	41.41
$	45.01	-	$	88.05	74,609	8.1	years	63.61	19,182	64.25
					246,535	4.8	years	42.53	185,758	36.33	3.8	years

Schedule of weighted-average assumptions used in valuing options

	Year ended December 31,
	2016		2015		2014
Dividend yield	1.60	%	1.40	%	1.27	%
Expected life	8.5	years	8.5	years	6	years
Expected volatility	40.6	%	40.9	%	43.8	%
Risk-free interest rate	1.90	%	1.79	%	2.10	%

Summary of nonvested restricted stock

		Weighted-
		Average
		Grant-Date
Restricted Stock	Shares	Fair Value
Nonvested at January 1, 2016	218,282	$	44.56
Granted	44,301		67.51
Vested	(77,494)		40.23
Forfeited	(2,075)		58.93
Nonvested at December 31, 2016	183,014		51.88

Vesting schedule of shares

	Shares
2016	58,992
2017	35,620
2018	31,167
2019	39,033
2020	3,405
Thereafter	14,797
	183,014

Summary of nonvested RSUs

		Weighted-
		Average
		Grant-Date
Restricted Stock Units	Shares	Fair Value
Nonvested at January 1, 2016	79,789	$	64.66
Granted	68,842		65.23
Vested	(40,116)		61.06
Forfeited	(639)		63.93
Nonvested at December 31, 2016	107,876		66.37