Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Stock-Based Compensation Expense and Related Tax Benefit [Table Text Block]

Stock-based compensation expense and the related tax benefit were as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
	(in thousands)
Stock options	$	602	$	713	$	1,741	$	2,005
Restricted stock units	4,595		1,969		10,834		8,374
Unrestricted stock awards	225		200		725		500
Phantom stock units	371		—		658		—
Total stock-based compensation	$	5,793	$	2,882	$	13,958	$	10,879

Related tax benefit	$	1,289	$	809	$	3,793	$	3,189

Stock Options, Valuation Assumptions [Table Text Block]

The fair values of stock options granted were estimated at the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Dividend yield⁽¹⁾	—	%	—	%	—	%	—	%
Expected volatility⁽¹⁾	33.7	%	—	%	33.5	%	34.5	%
Risk-free interest rate⁽¹⁾	1.3	%	—	%	1.3	%	1.7	%
Expected term (years)⁽¹⁾	5.5		—		5.5		5.5


⁽¹⁾	There were no employee stock options granted for the three months ended September 30, 2015.

Employee Stock Options Activity [Table Text Block]

A summary of our stock option activity is as follows:



	Shares		Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value⁽¹⁾		Weighted Average Grant Date Fair Value
	(in thousands)				(years)	(in thousands)
Outstanding, January 1, 2015	1,123		$	51.90	4.4	$	1,676
Granted	207		35.30					$	12.15
Exercised	(23	)	36.05			26
Forfeited	(17	)	37.47
Expired	(167	)	53.95
Outstanding, September 30, 2015	1,123		$	49.12	5.4	$	—

Outstanding, January 1, 2016	1,180		$	48.31	5.7	$	405
Granted	191		40.40					$	13.27
Exercised	(35	)	35.31			214
Forfeited	(36	)	35.29
Expired	(312	)	55.11
Outstanding, September 30, 2016	988		$	45.57	6.8	$	13,732

Exercisable September 30, 2016	563		$	51.57	5.1	$	6,024

Expected to vest, September 30, 2016	410		$	37.58	8.9	$	7,448

⁽¹⁾

The aggregate intrinsic value of outstanding stock options represents amounts that would have been received by the optionees had all in- the-money options been exercised on that date. Specifically, it is the amount by which the market value of our stock exceeded the exercise price of the outstanding in-the-money options before applicable income taxes, based on our closing stock price on the last business day of the period. The aggregate intrinsic value of stock options exercised during the period is calculated based on our stock price at the date of exercise.

Restricted Stock Units, Valuation Assumptions

The weighted-average assumptions used to estimate the fair value of performance-based restricted stock units granted and the resulting weighted average fair value are as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2015			2016			2015
Dividend yield⁽¹⁾	—		%	—		%	—		%	—		%
Expected volatility⁽¹⁾	28.8		%	—		%	30.0		%	30.1		%
Risk-free interest rate⁽¹⁾	0.8		%	—		%	0.7		%	0.7		%
Expected term (years)⁽¹⁾	2.3			—			1.8			2.1

Weighted average fair value⁽¹⁾	$	63.10		$	—		$	44.92		$	33.48


⁽¹⁾	There were no long-term performance restricted stock units granted for the three months ended September 30, 2015.

Restricted Stock Units Award Activity [Table Text Block]

The following table summarizes restricted stock unit activity:



	Number of Restricted Stock Units		Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value⁽¹⁾
	(in thousands)				(in thousands)
Outstanding, January 1, 2015	682
Granted⁽²⁾	319		$	35.30
Released	(288	)			$	11,852
Forfeited	(54	)
Outstanding, September 30, 2015	659

Outstanding, January 1, 2016	756
Granted⁽²⁾	196		$	41.58
Released	(280	)			$	10,823
Forfeited	(50	)
Outstanding, September 30, 2016	622

Vested but not released, September 30, 2016	5				$	277

Expected to vest, September 30, 2016	500				$	27,894


⁽¹⁾	The aggregate intrinsic value is the market value of the stock, before applicable income taxes, based on the closing price on the stock release dates or at the end of the period for restricted stock units expected to vest.


⁽²⁾	Restricted stock units granted in 2015 and 2016 do not include awards under the Performance Award Agreement for the respective years, as these awards are not granted until attainment of annual performance goals has been determined at the conclusion of the performance period, which had not occurred as of September 30, 2015 and 2016, respectively.

Schedule of Other Share-based Compensation, Activity [Table Text Block]

The following table summarizes phantom stock unit activity:



	Number of Phantom Stock Units		Weighted Average Grant Date Fair Value
	(in thousands)
Outstanding, January 1, 2016	—
Granted	63		$	40.11
Forfeited	(1	)
Outstanding, September 30, 2016	62

Expected to vest, September 30, 2016	56

Nonrestricted Stock Awards Activity [Table Text Block]

The following table summarizes unrestricted stock award activity:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
	(in thousands, except per share data)
Shares of unrestricted stock granted	4		6		17		14

Weighted average grant date fair value per share	$	53.96	$	33.91	$	42.24	$	36.51

Employee Stock Purchase Plan (ESPP) Activity [Table Text Block]

The following table summarizes ESPP activity:



	Three Months Ended September 30,		Nine Months Ended September 30,
	2016	2015	2016	2015
	(in thousands)
Shares of stock sold to employees⁽¹⁾	—	11	20	39


⁽¹⁾	Stock sold to employees during each fiscal quarter under the ESPP is associated with the offering period ending on the last day of the previous fiscal quarter. No stock was sold under the ESPP during the third quarter of 2016 because the ESPP had been suspended due to our delayed SEC filings. We became current with our SEC filings on September 2, 2016 and the ESPP is again active.