Accounting for Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

The following table summarizes stock option activity during the three-year period ended December 31, 2018:

Options	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2015		1,530,845		$	27.46
Granted		862,000			40.87
Exercised		(112,875	)		13.24
Forfeited		(176,500	)		39.32
Outstanding at December 31, 2016		2,103,470		$	32.72		4.86	$	12,265
Granted		808,500			37.23
Exercised		(202,328	)		13.62
Forfeited		(57,500	)		42.54
Outstanding at December 31, 2017		2,652,142		$	35.34		4.76	$	6,964
Granted		—			—
Exercised		(615,358	)		24.01
Forfeited		(383,784	)		39.59
Outstanding at December 31, 2018		1,653,000			38.53		4.28	$	3,610
Exercisable at December 31, 2016		675,152		$	21.40		3.45	$	9,646
Exercisable at December 31, 2017		984,374		$	29.84		3.44	$	6,534
Exercisable at December 31, 2018		788,125		$	38.15		3.71	$	2,200

Fair Value of Option on Date of Grant

The fair value of each option is estimated on the date of grant using the Black-Scholes option-pricing model in order to measure the compensation cost associated with the award. This model incorporates certain assumptions for inputs including a risk-free interest rate, expected dividend yield of the underlying Common Stock, expected option life and expected volatility in the market value of the underlying Common Stock. The following assumptions were used for options issued in the following periods:

	2018	2017	2016
Expected volatility	NA	33%	37%
Weighted average expected volatility	NA	33%	37%
Expected lives	NA	3 yrs.	3 yrs.
Risk-free interest rate	NA	1.49-1.93%	0.90-1.07%
Expected dividend yield	none	none	none

Restricted Stock Activity

The following table summarizes restricted stock activity during the three-year period ended December 31, 2018:

Unvested Restricted Shares	Shares			Weighted- Average Grant-Date Fair Value
Outstanding at December 31, 2015		179,026		$	34.92
Granted		141,784			39.73
Vested		(100,330	)		32.47
Forfeited		(9,999	)		40.99
Outstanding at December 31, 2016		210,481		$	39.02
Granted		237,542			37.30
Vested		(165,923	)		37.99
Forfeited		—			—
Outstanding at December 31, 2017		282,100		$	38.06
Granted		21,681			35.00
Vested		(130,684	)		38.62
Forfeited		(36,531	)		37.60
Outstanding at December 31, 2018		136,566		$	37.16

SARs Activity

The following table summarizes SARs activity during the three-year period ended December 31, 2018:

Stock Appreciation Rights	Units			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2015		1,049,850		$	34.61
Granted		244,000			40.64
Exercised		(18,750	)		24.28
Forfeited		(30,500	)		28.23
Outstanding at December 31, 2016		1,244,600		$	36.11		4.80	$	3,511
Granted		235,000			38.05
Exercised		(94,250	)		22.21
Forfeited		(193,000	)		32.53
Outstanding at December 31, 2017		1,192,350		$	38.17		4.36	$	2,278
Granted		—			—
Exercised		(204,250	)		26.35
Forfeited		—			—
Outstanding at December 31, 2018		988,100		$	40.61		3.57	$	2,064
Exercisable at December 31, 2016		424,992		$	34.49		4.39	$	2,315
Exercisable at December 31, 2017		613,808		$	37.68		3.72	$	1,904
Exercisable at December 31, 2018		683,600		$	41.21		3.09	$	1,728

RSU

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Restricted Stock Activity

The following table summarizes restricted stock unit activity during the year ended December 31 2018:

			Performance Based Awards
Unvested Restricted Stock Units	Time Vesting Shares		ROIC Target Shares		TSR Target Shares		Total
Outstanding at December 31, 2017		—		—		—		—
Granted		86,392		64,785		64,792		215,969
Vested		—		—		—		—
Forfeited		—		—		—		—
Outstanding at December 31, 2018		86,392		64,785		64,792		215,969