Stock Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Transactions of Stock Option Plans

The following table summarizes the transactions of the Company’s stock option plans for the three-year period ended December 31, 2018:

	Number of shares			Weighted- average exercise price
Options outstanding - December 31, 2015		369,612		$	22.35
Options granted		42,302		$	33.98
Options exercised		(27,656	)	$	20.59
Options forfeited		—		n/a
Options outstanding - December 31, 2016		384,258		$	23.75
Options granted		55,223		$	36.75
Options exercised		(53,198	)	$	22.83
Options forfeited		—		n/a
Options outstanding - December 31, 2017		386,283		$	25.74
Options granted		43,778		$	48.20
Options modified		80,642		$	52.44
Options exercised		(53,161	)	$	21.47
Options canceled		(80,642	)	$	37.04
Options forfeited		—		n/a
Options outstanding - December 31, 2018		376,900		$	28.95
Price range $ 18.08 — $ 19.21
(weighted-average contractual life of 2.7 years)		118,900		$	18.35
Price range $ 19.30 — $ 28.33
(weighted-average contractual life of 5.3 years)		119,139		$	27.17
Price range $ 28.34 — $ 48.20
(weighted-average contractual life of 8.2 years)		138,861		$	39.55
Options outstanding - December 31, 2018		376,900
Exercisable options —
December 31, 2016		242,522		$	21.01
December 31, 2017		239,043		$	21.59
December 31, 2018		321,122		$	27.16

Assumptions Used for Valuing Options Granted

The following assumptions were used for valuing options granted in the years ended December 31:

	2018			2017
Per share fair value of options granted during the period	$	18.50		$	14.38
Risk-free interest rate		2.59	%		2.06	%
Dividend yield		1.05	%		1.22	%
Volatility factor		43.2	%		46.6	%
Weighted-average expected life in years		5.3			5.3

Summary of Aggregate Intrinsic Value Related to Options

The following table summarizes the aggregate intrinsic value related to options exercised, outstanding and exercisable as of and for the years ended December 31:

	2018		2017
	(In thousands)
Exercised	$	1,590	$	814
Outstanding	$	8,390	$	7,966
Exercisable	$	7,722	$	5,921

Schedule of Fair Value of Nonvested Shares

The fair value of nonvested shares is determined based on the market price of the shares on the grant date.

	Shares			Fair value per share
Nonvested at December 31, 2015		120,248		$	26.99
Granted		29,268		$	33.98
Vested		(40,700	)	$	25.56
Forfeited		(3,500	)	$	29.18
Nonvested at December 31, 2016		105,316		$	29.41
Granted		50,519		$	40.69
Vested		(40,762	)	$	27.18
Forfeited		(3,600	)	$	33.37
Nonvested at December 31, 2017		111,473		$	35.21
Granted		32,268		$	49.10
Modified		30,488		$	52.47
Vested		(68,289	)	$	40.16
Canceled		(30,488	)	$	38.62
Forfeited		(2,550	)	$	36.83
Nonvested at December 31, 2018		72,902		$	42.58