Common Stock Common Stock (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based Payment Arrangement, Cost by Plan [Table Text Block]

The following table provides a summary of the impact of our outstanding stock-based compensation plans on the results of operations for the periods presented:

	Year Ended December 31,
	2019			2018			2017
	(in thousands)
Stock-based compensation expense	$	23,837		$	21,782		$	19,353
Income tax benefit	(5,780		)	(5,210		)	(7,372		)
Net stock-based compensation expense	$	18,057		$	16,572		$	11,981

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31, 2017
Expected term of award (in years)	6
Risk-free interest rate	2.0		%
Expected volatility	53.3		%
Weighted-average grant date fair value per share	$	38.58

Share-based Payment Arrangement, Stock Appreciation Right, Activity [Table Text Block]

	Year Ended December 31,
	2019						2018						2017
	Number of SARs	Weighted-Average Exercise Price		Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value		Number of SARs		Weighted-Average Exercise Price		Aggregate Intrinsic Value		Number of SARs	Weighted-Average Exercise Price		Aggregate Intrinsic Value
Outstanding at January 1,	290,258	$	46.64	4.6	$	125	298,220		$	47.39	$	2,490	244,078	$	41.36	$	7,620
Awarded	—	—		—	—		—		—		—		54,142	74.57		—
Modified	—	—		—	—		63,969		42.83		—		—	—		—
Expired	—	—		—	—		(71,931	)	46.34		—		—	—		—
Outstanding at December 31,	290,258	46.64		3.6	41		290,258		46.64		125		298,220	47.39		2,490
Exercisable at December 31,	276,775	45.28		3.4	41		260,101		44.88		125		223,865	43.28		2,267

Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

The following table presents the changes in non-vested time-based RSUs to all employees, including executive officers, for 2019:

	Shares		Weighted-Average Grant Date Fair Value per Share
Non-vested at December 31, 2018	618,407		$	54.16
Granted	588,899		40.34
Vested	(307,450	)	52.98
Forfeited	(103,930	)	45.62
Non-vested at December 31, 2019	795,926		45.51

The following table presents the weighted-average grant date fair value per share and related information as of/for the periods presented:

	As of/Year Ended December 31,
	2019		2018		2017
	(in thousands, except per share data)
Total intrinsic value of time-based awards vested	$	11,652	$	12,282	$	16,303
Total intrinsic value of time-based awards non-vested	20,829		18,404		24,334
Market price per share as of December 31,	26.17		29.76		51.54
Weighted-average grant date fair value per share	40.34		50.69		65.14

Restricted Stock Awards, Market-Based, Valuation assumptions [Table Text Block]

he weighted-average grant date fair value per PSU granted was computed using the Monte Carlo pricing model using the following assumptions:

	Year Ended December 31,
	2019		2018		2017
Expected term of award (in years)	3		3		3
Risk-free interest rate	2.5	%	2.4	%	1.4	%
Expected volatility	41.4	%	42.3	%	51.4	%

Schedule of Nonvested Performance-based Units Activity [Table Text Block]

The following table presents the change in non-vested market-based awards during 2019:

	Shares		Weighted-Average Grant Date Fair Value per Share
Non-vested at December 31, 2018	102,914		$	74.88
Granted	139,197		56.68
Vested	(20,969	)	94.02
Forfeited	—		—
Non-vested at December 31, 2019	221,142		61.61

The following table presents the weighted-average grant date fair value per share and related information as of/for the periods presented:

	As of/Year Ended December 31,
	2019		2018		2017
	(in thousands, except per share data)
Total intrinsic value of market-based awards vested	$	530	$	620	$	2,687
Total intrinsic value of market-based awards non-vested	5,787		3,063		2,698
Market price per share as of December 31,	26.17		29.76		51.54
Weighted-average grant date fair value per share	56.68		69.98		94.02