Equity-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Share Based Compensation [Abstract]

Details of Equity-Based Compensation Expense and Related Income Tax Benefit

The following table details equity-based compensation expense and the related income tax benefit:

	Three Months Ended June 30,				Six Months Ended June 30,
(Dollars in thousands)	2018		2017		2018		2017
Employee equity-based compensation expense:
Performance shares	$	1,074	$	905	$	2,010	$	1,773
Restricted stock units		454		286		934		575
Accelerated share-based termination benefits in connection with the merger		86		—		1,764		—
Total employee equity-based compensation expense	$	1,614	$	1,191	$	4,708	$	2,348
Deferred compensation stock equivalent units expense	$	53	$	161	$	181	$	322
Total tax benefit recognized for share-based expense	$	73	$	96	$	184	$	189

Fair Value of Performance Share Awards

The following table presents the key inputs used in the Monte Carlo simulation to calculate the fair value of the performance share awards in 2018 and 2017:

	Six Months Ended June 30,
	2018			2017
Stock price as of valuation date	$	54.00		$	43.60
Risk-free rate		2.46	%		1.61	%
Expected volatility		23.74	%		24.22	%
Expected dividends		2.96	%		3.44	%
Expected term (years)		3.00			3.00
Fair value	$	75.37		$	53.85

Summary of Outstanding Performance Share Awards

The following table summarizes outstanding performance share awards as of June 30, 2018 and changes during the six months ended June 30, 2018:

(Dollars in thousands, except grant date fair value)	Shares			Weighted-Avg. Grant Date Fair Value		Aggregate Intrinsic Value
Unvested shares outstanding at December 31, 2017		200,631		$	39.19
Granted		67,747		$	75.37
Forfeited		(5,082	)	$	47.90
Unvested shares outstanding at June 30, 2018		263,296		$	48.33	$	13,389

Summary of Outstanding RSU Awards

The following table summarizes outstanding RSU awards as of June 30, 2018 and changes during the six months ended June 30, 2018:

(Dollars in thousands, except grant date fair value)	Shares			Weighted-Avg. Grant Date Fair Value		Aggregate Intrinsic Value
Unvested shares outstanding at December 31, 2017		67,871		$	32.87
Granted		42,193		$	51.59
Vested		(1,000	)	$	42.92
Forfeited		(3,694	)	$	45.36
Unvested shares outstanding at June 30, 2018		105,370		$	39.84	$	5,358