Accounting for Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

The following table summarizes stock option activity during the three year period ended December 31, 2016:

Options	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2013		1,943,176		$	12.19			$
Granted		605,000			30.15
Exercised		(731,142	)		9.84
Forfeited		(142,500	)		18.94
Outstanding at December 31, 2014		1,674,534		$	19.14		5.10	$	29,886
Granted		524,534			41.97
Exercised		(571,723	)		16.21
Forfeited		(96,500	)		28.47
Outstanding at December 31, 2015		1,530,845		$	27.46		4.97	$	30,573
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
Exercisable at December 31, 2014		632,034		$	10.13		3.97	$	16,744
Exercisable at December 31, 2015		439,561		$	12.18		3.51	$	15,480
Exercisable at December 31, 2016		675,152		$	$21.40		3.45	$	9,646

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:

	2016	2015	2014
Expected volatility	37%	35%	37%
Weighted average expected volatility	37%	35%	37%
Expected lives	3 yrs.	3 yrs.	3 yrs.
Risk-free interest rate	0.90-1.07%	1.00%	0.60-1.00%
Expected dividend yield	none	none	none

Restricted Stock Activity

The following table summarizes restricted stock activity during the three year period ended December 31, 2016:

Unvested Restricted Shares	Shares			Weighted- Average Grant-Date Fair Value
Nonvested at December 31, 2013		243,967		$	17.43
Granted		104,584			27.79
Vested		(129,092	)		16.45
Forfeited		(42,375	)		19.77
Outstanding at December 31, 2014		177,084		$	23.70
Granted		108,026			44.01
Vested		(82,084	)		23.86
Forfeited		(24,000	)		30.87
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

SARs Activity

The following table summarizes SARs activity during the three year period ended December 31, 2016:

Stock Appreciation Rights	Units			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2013		495,000		$	19.19
Granted		754,000			34.70
Exercised		(68,750	)		19.10
Forfeited		(120,000	)		21.46
Outstanding at December 31, 2014		1,060,250		$	29.97		6.11	$	9,991
Granted		259,600			43.97
Exercised		(167,500	)		23.90
Forfeited		(102,500	)		27.82
Outstanding at December 31, 2015		1,049,850		$	34.61		5.46	$	13,425
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
Exercisable at December 31, 2014		35,000		$	19.43		5.53	$	602
Exercisable at December 31, 2015		153,575		$	38.12		5.59	$	1,425
Exercisable at December 31, 2016		424,992		$	34.49		4.39	$	2,315