Equity-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share-based Compensation [Abstract]

Summary of Compensation Expense Connection with Awards

The Company recognized the following compensation expense in connection with awards that vested under the Plan, the Prior Plan, and the Non-Employee Directors Plan along with the related tax benefits recognized during the years ended December 31 (in thousands):

	2017		2016		2015
Expense recognized under the Prior Plan	$	1,059	$	1,937	$	1,953
Expense recognized under the Plan	5,643		3,993		1,938
Expense recognized under the Non-Employee Directors Plan	420		443		—
Total stock compensation expense	$	7,122	$	6,373	$	3,891
Tax benefits recognized related to stock compensation expense	$	2,133	$	2,485	$	1,518

Schedule of Number of Awards and Weighted Average Grant Date Fair Value

The following table provides the number of stock unit awards granted and restricted shares issued during the years ended December 31, along with the weighted-average grant-date fair value of each award:

	2017			2016			2015
Awards	Number of Awards	Weighted Average Grant Date Fair Value		Number of Awards	Weighted Average Grant Date Fair Value		Number of Awards	Weighted Average Grant Date Fair Value
Options	25,000	$	12.85	—	$	—	37,500	$	7.67
Deferred stock units	10,170	$	34.42	11,945	$	29.30	—	$	—
Restricted shares	2,034	$	34.42	3,185	$	29.30	21,318	$	17.48
Restricted stock units	133,548	$	36.56	141,982	$	25.44	212,419	$	17.78
Performance stock units	108,748	$	42.72	—	$	—	396,714	$	19.78

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following table provides the weighted average assumptions used to value stock options issued during the year ended December 31:

Year of Grant	Fair Value		Expected Life (in years)	Expected Stock Volatility		Risk-free Interest Rate		Expected Dividend Yield
2017	$	12.85	4.00	35.7	%	1.7	%	—	%
2015	$	7.67	4.00	35.7	%	1.5	%	—	%

Summary of Ranges of Outstanding and Exercisable Options

The following table summarizes the ranges of outstanding and exercisable options at December 31, 2017:

Range of Exercise Prices	Options Outstanding	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Options Exercisable	Weighted Average Exercise Price
$8.90 – $9.32	28,750	2.70	$	8.90	28,750	$	8.90
$9.33 – $11.73	92,441	3.70	$	9.74	92,441	$	9.74
$11.74 – $17.94	39,475	1.70	$	13.72	39,475	$	13.72
$17.95 – $23.80	37,000	0.69	$	22.16	37,000	$	22.16
$23.81 – $43.05	50,000	8.57	$	33.90	—	$	—
	247,666				197,666

Summary of Stock Options Transactions

The following table summarizes information about stock option transactions:

	Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
Balance at January 1, 2015	569,319		$	15.88
Granted	37,500		25.44
Exercised	(119,096	)	15.13
Expired / Forfeited	(29,374	)	20.28
Balance at December 31, 2015	458,349		$	16.57
Exercised	(175,125	)	19.08
Forfeited	(6,000	)	18.22
Balance at December 31, 2016	277,224		$	14.95
Granted	25,000		42.35
Exercised	(42,058	)	16.02
Forfeited	(12,500	)	25.44
Balance at December 31, 2017	247,666		$	17.01	5.27	$	4,194,000

Summary of Information About Restricted Stock Units and Weighted Average Grant Date Fair Value

The following table summarizes information about non-vested restricted stock units, performance stock units (that will convert to shares upon vesting) and restricted shares:

	Restricted Stock Units		Weighted Average Grant Date Fair Value		Restricted Shares		Weighted Average Grant Date Fair Value		Performance Stock Units (2) (3)		Weighted Average Grant Date Fair Value		Deferred Stock Units (1)	Weighted Average Grant Date Fair Value
Balance at December 31, 2016	536,164		$	17.79	7,361		$	17.07	396,714		$	19.78	11,945	$	29.30
Granted	133,548		36.56		2,034		34.42		108,748		42.72		10,170	34.42
Vested	(202,788	)	15.71		(5,137	)	23.75		—		—		—	—
Forfeited	(25,108	)	25.88		—		—		(25,000	)	25.44		—	—
Balance at December 31, 2017	441,816		$	23.96	4,258		$	17.30	480,462		$	24.68	22,115	$	31.65

(1) Vested and issued upon retirement.

Aggregate Intrinsic Value of Options Exercised and Aggregate Fair Value of Restricted Stock Units and Restricted Shares that Vested

The following table sets forth the aggregate intrinsic value of options exercised and aggregate fair value of restricted stock units and restricted shares that vested during the years ended December 31 (in thousands):

	2017		2016		2015
Aggregate intrinsic value of options exercised	$	628	$	2,439	$	1,089
Aggregate fair value of vested restricted stock units	$	6,756	$	4,368	$	6,578
Aggregate fair value of vested restricted shares	$	70	$	247	$	111
Aggregate fair value of vested deferred stock units	$	350	$	443	$	—

PSUs Eligible for Conversion to Cash

The following table provides the number of PSUs which will convert to cash for the years ending December 31:

	2016			2015
Awards	Number of Units (2)	Grant Date Fair Value (in $000s)		Number of Units (3)	Grant Date Fair Value (in $000s)
Performance stock units (1)	128,000	$	3,100	219,000	$	4,039

(1) There were no performance stock units that convert to cash granted to participants in 2017.

(2) The participants earned 200% of target aggregating 256,000 PSUs earned. This award will convert to cash and be payable in January 2019.

(3) The participants earned 200% of target aggregating 438,000 PSUs earned. This award will be converted to cash and will be paid to participants in the first quarter of 2018 at the trailing 90-day closing price of the Company's common stock as of December 31, 2017.

Schedule of Compensation Expense Recognized from Change in Fair Value and Vesting of Performance Stock Units

The following table summarizes the compensation expense recognized from the change in fair value and vesting of performance stock units awarded for the years ended December 31 (in thousands):

	2017		2016		2015
Performance stock unit compensation expense	$	3,591	$	10,377	$	6,965

Cash Paid to Settle Liability Awards

The following table provides the number of restricted stock units credited to active participant accounts, balance of vested and unvested restricted stock units within active participant accounts, payments made with respect to restricted stock units issued under the MSPP, and MSPP expense during years ended December 31:

	2017		2016		2015
Restricted stock units credited	84,299		198,155		94,047
Restricted stock units balance, vested and unvested	389,189		646,669		519,668
Share-based liabilities paid, in thousands	$	6,058	$	3,137	$	1,901
MSPP expense, in thousands	$	2,432	$	8,565	$	2,767