Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Schedule of unvested restricted stock awards

The following tables summarize the unvested restricted stock awards at December 31, 2017 and 2016.

	Years Ended December 31,
	2017				2016
Perfomance Awards	Shares		Weighted- Average Grant Date Fair Value		Shares		Weighted- Average Grant Date Fair Value
Unvested at beginning	33,226		$	42.60	—		$	—
Issued	36,523		57.49		34,957		42.60
Forfeited	(2,520	)	41.93		(1,731	)	42.60
Vested	(4,891	)	54.70		—		—
Unvested at end	62,338		$	50.45	33,226		$	42.60

	Years Ended December 31,
	2017				2016
Time Vested Awards	Shares		Weighted- Average Grant Date Fair Value		Shares		Weighted- Average Grant Date Fair Value
Unvested at beginning	262,966		$	33.60	369,093		$	24.43
Issued	91,097		62.70		104,775		46.39
Forfeited	(2,360	)	49.52		(8,749	)	39.82
Vested	(187,660	)	30.07		(202,153	)	23.22
Unvested at end	164,043		$	53.57	262,966		$	33.87

Schedule of activity of stock options

Below is a summary of stock option activity for the twelve months ended December 31, 2017, 2016 and 2015. The information excludes restricted stock units and awards.

	Years Ended December 31,
	2017				2016				2015
	Shares		Weighted- Average Exercise Price		Shares		Weighted- Average Exercise Price		Shares		Weighted- Average Exercise Price
Beginning balance	216,859		$	8.80	298,740		$	9.97	759,683		$	11.36
Issued	—		—		3,000		49.49		5,000		46.50
Exercised	(72,535	)	8.19		(77,144	)	14.48		(443,912	)	12.03
Forfeited	—		—		(1,100	)	15.48		(12,380	)	29.58
Expired	(1,100	)	5.76		(6,637	)	12.87		(9,651	)	18.19
Ending balance	143,224		$	9.13	216,859		$	8.80	298,740		$	9.97

Schedule of stock option by exercise price range

The following summarizes information about stock options outstanding at December 31, 2017. 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	99,975	$	5.76	1.02
$10.73	$11.40	35,339	10.84		0.60
$11.41	$24.86	1,160	22.11		5.26
$24.87	$49.91	6,750	47.83		8.12
		143,224	$	9.13	1.29

Exercisable:		Stock Options	Weighted-Average
Range of Exercise Prices		Exercisable	Exercise Price
$5.76	$10.72	65,277	$	5.76
$10.73	$11.40	35,339	10.84
$11.41	$24.86	—	—
$24.87	$49.91	2,000	47.62
		102,616	$	8.33

Schedule of valuation assumptions used for stock options

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option pricing model with the assumptions as shown in the table below used for grants during the years ended December 31, 2017, 2016 and 2015.

	Years Ended December 31,
	2017	2016			2015
Expected volatility	n/a	24.23		%	31.21		%
Weighted-Average volatility	n/a	24.23		%	31.21		%
Expected dividends	—	—			—
Expected term (in years)	n/a	7.0			7.0
Risk-free rate	n/a	1.37		%	1.64		%
Weighted-average fair value (grant date)	n/a	$	14.27		$	16.73

Schedule of cash proceeds received from share-based payment awards

Cash proceeds, tax benefits and intrinsic value related to total stock options exercised is as follows:

	Years Ended December 31,
(dollars in thousands)	2017		2016		2015
Proceeds from stock options exercised	$	372	$	955	$	5,176
Tax benefits realized from stock compensation	—		400		2,984
Intrinsic value of stock options exercised	3,888		2,824		11,042