Stock Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of stock compensation expense and related net tax benefit

The following table presents a summary of the total share-based compensation expense and the related net tax benefit associated with the Company’s various employee share-based compensation plans for the three and nine months ended September 30, 2017 and 2016:

($ in thousands)	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Stock compensation costs	$	5,665	$	4,763	$	15,780	$	13,973
Related net tax benefits for stock compensation plans	$	151	$	14	$	4,614	$	1,019

Summary of activity for time-based and performance-based restricted stock units

The following table presents a summary of the activity for the Company’s time-based and performance-based RSUs for the nine months ended September 30, 2017 based on the target amount of awards:

	Nine Months Ended September 30, 2017
	Time-Based RSUs				Performance-Based RSUs
	Shares		Weighted Average Grant-Date Fair Value		Shares		Weighted Average Grant-Date Fair Value
Outstanding, beginning of period	1,218,714		$	35.92	410,746		$	35.27
Granted	370,514		54.71		131,597		56.59
Vested	(299,164	)	36.68		(118,044	)	36.85
Forfeited	(131,472	)	40.05		—		—
Outstanding, end of period	1,158,592		$	41.26	424,299		$	41.44