Stock-based Compensation and Benefits - (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of weighted average assumptions using Black-Scholes option-pricing model

Below are the weighted average assumptions used in the Black-Scholes option pricing model to determine fair value of the Company’s stock options granted in 2016, 2015 and 2014:

	2016		2015		2014
Weighted average fair value	$	4.24	$	4.37	$	6.08
Weighted average risk-free interest rate (1)		1.47%		1.59%		2.02%
Expected volatility (2)		22.47%		23.87%		33.94%
Expected term (years) (3)		6.09		6.01		6.01
Dividend yield (4)		1.02%		1.05%		1.06%

(1)	The risk-free rate for the expected term of the options was based on the U.S. Treasury yield curve at the date of grant and based on the expected term.
(2)	Expected volatility was calculated using a time-based weighted migration of the Company’s own stock price volatility coupled with those of a peer group of eight comparable publicly traded companies for a period commensurate with the expected term of the options.
(3)	The expected term was estimated to be the average of the contractual vesting term and time to expiration.
(4)	The dividend yield was assumed to be zero for grants made prior to the initial public offering and for subsequent grants was assumed to be $0.05 per share per quarter and $0.07 per share per quarter after October 18, 2016 in accordance with the Company’s dividend policy at the time of grant.

Summary of Option Activity

The following table summarizes stock option activity for 2016:

				Weighted
				average
		Weighted		remaining
		average		contractual	Aggregate
		exercise		term in	intrinsic
	Options	price		years	value
Outstanding at December 31, 2015	2,596,251	$	19.84	4.77	$	3,968
Granted	175,693		19.74
Forfeited	(39,768)		19.25
Surrendered	(451,766)		19.98
Exercised	(83,004)		19.91
Expired	(11,484)		19.68
Outstanding at December 31, 2016	2,185,922	$	19.81	4.85	$	7,753
Options exercisable at December 31, 2016	1,851,858	$	19.91	3.46	$	6,060
Options expected to vest	313,403	$	19.34	8.32	$	1,266

Summary of outstanding stock options

The following table summarizes the Company’s outstanding stock options:

				Options outstanding				Options exercisable
					Weighted average
				Number	remaining contractual	Weighted average		Number	Weighted average
Range of exercise price				outstanding	life (years)	exercise price		exercisable	exercise price
$	18.00	-	18.99	162,815	6.72	$	18.51	91,978	$	18.57
$	19.00	-	19.99	279,718	8.77	$	19.38	40,515	$	19.17
$	20.00 and above			1,743,389	3.32	$	20.02	1,719,365	$	20.00

Summary of Restricted Stock Activity

The following table summarizes restricted stock activity during 2016:

		Weighted				Weighted
	Restricted	average grant-		Performance		average grant-
	shares	date fair value		stock units		date fair value
Unvested at December 31, 2015	836,031	$	15.42	—	$	—
Vested	(249,766)		15.99	—		—
Granted	122,992		19.15	91,342		18.22
Forfeited	(28,597)		18.95	(6,047)		18.22
Surrendered	(181,389)		15.50	—		—
Unvested at December 31, 2016	499,271	$	15.82	85,295	$	18.22