Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

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

Schedule of unvested restricted stock awards

The following tables summarize the unvested restricted stock awards activity for the three months ended March 31, 2018 and 2017.

	Three Months Ended March 31,
	2018					2017
Perfomance Awards	Shares			Weighted-Average Grant Date Fair Value		Shares		Weighted-Average Grant Date Fair Value
Unvested at beginning		62,338		$	50.45		33,226	$	42.60
Issued		42,533			60.45		36,523		57.49
Forfeited		(5,913	)		50.28		—		—
Vested		—			—		—		—
Unvested at end		98,958		$	54.76		69,749	$	50.40

	Three Months Ended March 31,
	2018					2017
Time Vested Awards	Shares			Weighted-Average Grant Date Fair Value		Shares			Weighted-Average Grant Date Fair Value
Unvested at beginning		164,043		$	53.57		262,966		$	33.60
Issued		94,344			60.45		91,097			62.70
Forfeited		(5,165	)		55.60		(371	)		42.93
Vested		(77,384	)		49.67		(176,134	)		28.73
Unvested at end		175,838		$	58.92		177,558		$	53.34

Schedule of activity of stock options

Below is a summary of stock option activity for the three months ended March 31, 2018 and 2017. The information excludes restricted stock units and awards.

	Three Months Ended March 31,
	2018					2017
	Shares			Weighted-Average Exercise Price		Shares			Weighted-Average Exercise Price
Beginning balance		143,224		$	9.13		216,859		$	8.80
Issued		—			—		—			—
Exercised		(32,230	)		10.48		(2,675	)		24.67
Forfeited		(500	)		24.86		—			—
Expired		—			—		—			—
Ending balance		110,494		$	8.67		214,184		$	8.60

Schedule of stock option by exercise price range

The following summarizes information about stock options outstanding at March 31, 2018. The information excludes restricted stock units and awards.

						Weighted-Average
Outstanding:		Stock Options		Weighted-Average		Remaining
Range of Exercise Prices		Outstanding		Exercise Price		Contractual Life
$5.76	$10.72		97,995	$	5.76		0.78
$10.73	$11.40		5,089		11.17		3.63
$11.41	$24.86		660		20.03		4.82
$24.87	$49.91		6,750		47.83		7.87
			110,494	$	8.67		1.36

Exercisable:		Stock Options		Weighted-Average
Range of Exercise Prices		Exercisable		Exercise Price
$5.76	$10.72		80,646	$	5.76
$10.73	$11.40		5,089		11.17
$11.41	$24.86		660		20.03
$24.87	$49.91		2,000		47.62
			88,395	$	7.13

Schedule of valuation assumptions used for stock options

There were no grants of stock options during the three months ended March 31, 2018.

	Three Months Ended		Years Ended December 31,
	March 31, 2018		2017		2016
Expected volatility		n/a		n/a		24.23	%
Weighted-Average volatility		n/a		n/a		24.23	%
Expected dividends		—		—		—
Expected term (in years)		n/a		n/a		7.0
Risk-free rate		n/a		n/a		1.37	%
Weighted-average fair value (grant date)		n/a		n/a	$	14.27