Stock Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2019

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 benefits associated with the Company’s various employee share-based compensation plans for the three months ended March 31, 2019 and 2018:

($ in thousands)	Three Months Ended March 31,
	2019		2018
Stock compensation costs	$	7,444	$	6,158
Related net tax benefits for stock compensation plans	$	4,707	$	4,778

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

The following table presents a summary of the activities and pricing information for the Company’s time-based and performance-based RSUs that will be settled in shares for the three months ended March 31, 2019. The number of outstanding performance-based RSUs stated below assumes the associated performance targets will be met at the target level:

	Three Months Ended March 31, 2019
	Time-Based RSUs				Performance-Based RSUs
	Shares		Weighted-Average Grant Date Fair Value		Shares		Weighted-Average Grant Date Fair Value
Outstanding, at beginning of period	1,121,391		$	51.22	411,290		$	49.93
Granted	475,833		52.75		134,600		54.64
Vested	(350,755	)	31.38		(159,407	)	29.18
Forfeited	(10,168	)	56.23		—		—
Outstanding, at end of period	1,236,301		$	57.40	386,483		$	60.13

The following table presents a summary of the activities for the Company’s time-based RSUs that will be settled in cash for the three months ended March 31, 2019:

	Three Months Ended March 31, 2019
	Shares
Outstanding, at beginning of period	—
Granted	12,145
Vested	—
Forfeited	—
Outstanding, at end of period	12,145