Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of stock options outstanding by exercise price range

The following summarizes information about stock options outstanding and exercisable at December 31, 2016:

	Options outstanding				Options exercisable
Range of exercise prices per share	Number outstanding	Weighted average exercise price per share		Weighted average contractual term (in years)	Number exercisable	Weighted average exercise price per share		Weighted average contractual term (in years)
$10.56 - 12.80	289,512	$	11.83	3.50	289,512	$	11.83	3.50
$13.20 - 16.24	1,044,881	16.20		5.99	1,044,881	16.20		5.99
$19.97 - 21.10	62,422	20.49		3.39	62,422	20.49		3.39
$28.43 - 32.81	703,378	31.58		8.58	295,439	29.88		7.76
$23.78 - 25.14	353,202	24.60		4.49	353,202	24.60		4.49
$10.56 - 32.81	2,453,395	$	21.41	6.16	2,045,456	$	19.14	5.56

Summary of activity for Corporation's stock options

A summary of activity for the Corporation's stock options as of and during the years ended December 31, 2016, 2015 and 2014 is presented below:

	Non-vested stock options outstanding						Stock options outstanding
	Number of options		Weighted- average exercise price per share		Weighted- average grant date fair value per share		Number of options		Weighted- average exercise price per share
Outstanding at December 31, 2013	414,080		$	24.29	$	7.19	1,073,990		$	26.84
Granted	190,011		29.45		9.64		190,011		29.45
Exercised	—		—		—		(72,936	)	24.67
Vested	(148,016	)	23.43		6.98		—		—
Expired or forfeited	(23,876	)	25.67		7.79		(153,754	)	37.50
Outstanding at December 31, 2014	432,199		26.75		8.30		1,037,311		25.90
Granted	244,165		30.18		8.40		244,165		30.18
Acquired	—		—		—		132,883		12.93
Exercised	—		—		—		(310,985	)	25.10
Vested	(150,224	)	25.57		7.80		—		—
Expired or forfeited	(46,385	)	27.99		8.50		(48,635	)	28.18
Outstanding at December 31, 2015	479,755		$	28.75	$	8.49	1,054,739		$	25.38
Acquired	—		—		—		1,466,408		15.08
Granted	441,167		32.81		6.15		441,167		32.81
Exercised	—		—		—		(450,296	)	20.02
Vested	(454,360	)	28.74		8.49		—		—
Forfeited/expired	(58,623	)	31.10		7.17		(58,623	)	31.10
Outstanding at December 31, 2016	407,939		$	32.81	$	6.15	2,453,395		$	21.41
Exercisable/vested at December 31, 2016							2,045,456		$	19.14

Assumptions of Black-Scholes option pricing model

The fair value of the stock options granted during the years ended December 31, 2016, 2015 and 2014 were estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions.

	2016		2015		2014
Expected dividend yield	3.30	%	3.50	%	3.00	%
Risk-free interest rate	1.39	%	1.78	%	2.16	%
Expected stock price volatility	27.9	%	39.1	%	42.2	%
Expected life of options — in years	6.5		7.0		7.0
Weighted average fair value of options granted	$6.15		$8.40		$9.64

Summary of activity for restricted stock units and awards

A summary of the activity for restricted stock units during the year ended December 31, 2016 is presented below:

	Number of units		Weighted-average grant date fair value per unit
Outstanding at December 31, 2015	207,989		$	26.41
Granted	165,876		37.41
Converted into shares of common stock	(67,331	)	24.54
Forfeited/expired	(8,177	)	31.19
Outstanding at December 31, 2016	298,357		$	32.81

The following table provides information regarding nonvested restricted stock awards:

Nonvested restricted stock awards	Number of awards		Weighted-average acquisition-date fair value
Nonvested at January 1, 2016	—		$	—
Acquired	484,892		46.23
Vested	(118,493	)	46.23
Forfeited	(508	)	46.23
Nonvested at December 31, 2016	365,891		$	46.23