Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Share-based Payment Arrangement [Abstract]

Summary of Stock Option Assumptions

The following weighted average assumptions were used to determine the fair value of the stock options granted on the original grant date for expense recognition purposes for options granted during the six months ended June 30, 2019 and 2018 using a Black Scholes-Merton Model:

	Six months ended
	June 30, 2019			June 30, 2018
Directors and Officers:
Expected dividend rate	$	0.32		$	0.26
Expected volatility	29.54		%	29.73		%
Risk-free interest rate	2.40		%	2.20		%
Expected life (in years)	5.0			5.0
Employees:
Expected dividend rate	$	0.32		$	0.26
Expected volatility	29.54		%	29.82		%
Risk-free interest rate	2.40		%	2.48		%
Expected life (in years)	5.0			5.0

Summary of Stock Options Outstanding

The following is a summary of stock options vested and exercisable as of June 30, 2019:

Range of Exercise Prices					Number of Shares	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Intrinsic Value (in thousands)
$	7.18	-	$	33.20	386,282	5.57	$	21.63	$	11,028
$	33.40	-	$	40.87	190,504	7.43	35.57		2,784
$	41.37	-	$	50.18	6,070	0.87	41.37		53
			Total		582,856	6.13	$	26.39	$	13,865

The following is a summary of stock options vested and exercisable as of June 30, 2018:

Range of Exercise Prices					Number of Shares	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Intrinsic Value (in thousands)
$	4.54	-	$	32.80	425,351	5.59	$	17.47	$	6,711
$	32.85	-	$	34.10	67,654	5.18	34.02		1
$	34.15	-	$	39.00	21,607	8.73	35.10		—
			Total		514,612	5.67	$	20.39	$	6,712

Summary of Stock Option Activity

A summary of option activity under the plans is as follows:

	Shares		Weighted Average Exercise Price
Outstanding at December 31, 2018	2,445,849		$	30.77
Granted	1,944,820		41.39
Exercised	(282,735	)	27.18
Forfeited or Expired	(225,525	)	36.37
Outstanding at June 30, 2019	3,882,409		$	36.02
Exercisable at June 30, 2019	582,856		$	26.39

Summary of Unvested Restricted Stock Awards

A summary of the unvested restricted stock awards is as follows:

 

	Shares		Weighted Average Grant Date Fair Value
Unvested at December 31, 2018	292,450		$	28.54
Granted	112,018		40.92
Vested	(106,644	)	27.21
Forfeited	(11,243	)	33.52
Unvested at June 30, 2019	286,581		$	33.68

Summary of Share-Based Compensation Expense

A summary of share-based compensation is as follows: 

	Three months ended				Six months ended
	June 30, 2019		June 30, 2018		June 30, 2019		June 30, 2018
Grant date fair value of awards during the period:	(in thousands)
Options	$	127	$	53	$	20,071	$	12,580
Restricted stock	876		1,247		4,584		3,361
Total	$	1,003	$	1,300	$	24,655	$	15,941
Share-based compensation expense:
Options	$	2,057	$	1,368	$	3,282	$	2,126
Restricted stock	986		607		1,791		1,573
Total	$	3,043	$	1,975	$	5,073	$	3,699
Income tax benefit/(deficiency) related to share-based compensation:
Options	$	488	$	300	$	731	$	601
Restricted stock	304		57		455		219
Total	$	792	$	357	$	1,186	$	820