Stock Compensation Plans

Pursuant to the Company’s 2016 Stock Incentive Plan, as amended, the Company may issue stocks, stock options, restricted stock awards (“RSAs”), RSUs, stock appreciation rights, stock purchase warrants, phantom stock and dividend equivalents to eligible employees, consultants, other service providers, and non-employee directors of the Company and its subsidiaries. There were no outstanding stock awards other than RSUs as of December 31, 2018, 2017 and 2016. An aggregate of 14.0 million shares of common stock were authorized under the 2016 Stock Incentive Plan, and the total number of shares available for grant was approximately 4.2 million as of December 31, 2018.

The following table presents a summary of the total share-based compensation expense and the related net tax benefits associated with the Company’s various employee share-based compensation plans for the years ended December 31, 2018, 2017 and 2016:




($ in thousands)	Year Ended December 31,
($ in thousands)	2018		2017		2016
Stock compensation costs	$	30,937	$	24,657	$	22,102
Related net tax benefits for stock compensation plans	$	5,089	$	4,775	$	1,055

RSUs — RSUs are granted under the Company’s long-term incentive plan at no cost to the recipient. RSUs vest ratably over three years or cliff vest after three or five years of continued employment from the date of the grant. RSUs entitle the recipient to receive cash dividend equivalents to any dividends paid on the underlying common stock during the period the RSUs are outstanding. RSU dividends are accrued during the vesting period and are paid at the time of vesting. While a portion of RSUs are time-vesting awards, others vest subject to the attainment of specified performance goals referred to as “Performance-based RSUs.” All RSUs are subject to forfeiture until vested.

Performance-based RSUs are granted at the target amount of awards. Based on the Company’s attainment of specified performance goals and consideration of market conditions, the number of shares that vest can be adjusted to a minimum of zero and to a maximum of 200% of the target. The amount of performance-based RSUs that are eligible to vest is determined at the end of each performance period and is then added together to determine the total number of performance shares that are eligible to vest. Performance-based RSUs cliff vest three years from the date of each grant.

Compensation costs for the time-based awards are based on the quoted market price of the Company’s stock at the grant date. Compensation costs associated with performance-based RSUs are based on grant date fair value which considers both market and performance conditions, and is subject to subsequent adjustments based on the changes in the Company’s projected outcome of the performance criteria. Compensation costs of both time-based and performance-based awards are recognized on a straight-line basis from the grant date until the vesting date of each grant.

The following table presents a summary of the activities for the Company’s time-based and performance-based RSUs for the year ended December 31, 2018. The number of outstanding performance-based RSUs stated below assumes the associated performance targets will be met at the target level.




	Year Ended December 31, 2018
	Time-Based RSUs				Performance-Based RSUs
	Shares		Weighted- Average Grant Date Fair Value		Shares		Weighted- Average Grant Date Fair Value
Outstanding, beginning of year	1,166,580		$	42.00	424,299		$	41.44
Granted	427,805		66.86		120,286		70.13
Vested	(349,939	)	39.84		(133,295	)	41.15
Forfeited	(123,055	)	50.48		—		—
Outstanding, end of year	1,121,391		$	51.22	411,290		$	49.93

The weighted-average grant date fair value of the time-based awards granted during the years ended December 31, 2018, 2017 and 2016 was $66.86, $55.28 and $31.86, respectively. The weighted-average grant date fair value of the performance-based awards granted during the years ended December 31, 2018, 2017 and 2016 was $70.13, $56.59 and $29.18, respectively. The total fair value of time-based awards that vested during the years ended December 31, 2018, 2017 and 2016 was $23.1 million, $17.2 million and $4.2 million, respectively. The total fair value of performance-based awards that vested during the years ended December 31, 2018, 2017 and 2016 was $16.2 million, $13.0 million and $4.4 million, respectively.

As of December 31, 2018, there were $31.9 million and $11.6 million of total unrecognized compensation costs related to unvested time-based and performance-based RSUs, respectively. These costs are expected to be recognized over a weighted-average period of 1.91 years and 1.80 years, respectively.

Stock Purchase Plan — The 1998 Employee Stock Purchase Plan (the “Purchase Plan”) provides eligible employees of the Company the right to purchase shares of its common stock at a discount. Employees could purchase shares at 90% of the fair market price subject to an annual purchase limitation of $22,500 per employee. As of December 31, 2018, the Purchase Plan qualifies as a non-compensatory plan under Section 423 of the Internal Revenue Code and, accordingly, no compensation expense has been recognized. 2,000,000 shares of the Company’s common stock have been made available-for-sale under the Purchase Plan. During the years ended December 31, 2018 and 2017, 51,541 shares totaling $2.8 million and 45,343 shares totaling $2.3 million, respectively, have been sold to employees under the Purchase Plan. As of December 31, 2018, there were 475,146 shares available under the Purchase Plan.