Stock Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of stock compensation expense and related net tax benefits

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, 2019, 2018 and 2017:

($ in thousands)	Year Ended December 31,
	2019		2018		2017
Stock compensation costs	$	30,761	$	30,937	$	24,657
Related net tax benefits for stock compensation plans	$	4,792	$	5,089	$	4,775

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

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

	Time-Based RSUs				Performance-Based RSUs
	Shares		Weighted- Average Grant Date Fair Value		Shares		Weighted- Average Grant Date Fair Value
Outstanding, January 1, 2019	1,121,391		$	51.22	411,290		$	49.93
Granted	500,145		52.46		134,600		54.64
Vested	(387,273	)	31.98		(159,407	)	29.18
Forfeited	(94,395	)	57.48		—		—
Outstanding, December 31, 2019	1,139,868		$	57.78	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 year ended December 31, 2019:

	Shares
Outstanding, January 1, 2019	—
Granted	12,145
Vested	—
Forfeited	(507	)
Outstanding, December 31, 2019	11,638