Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Attributable to Parent [Abstract]

Schedule of Common Stock Outstanding Roll Forward

Changes in the shares of outstanding common stock were as follows:

	Year Ended December 31,
	2017	2016		2015
Common Shares Outstanding:
Balance at beginning of year	20,968,707	—		—
Shares issued from equity-based compensation	67,380	—		—
Reclassification	—	15,968,707		—
Shares issued	—	5,000,000		—
Balance at end of year	21,036,087	20,968,707		—
Class A Common Stock Outstanding:
Shares outstanding at beginning of year	—	13,803,183		13,795,530
Share dividend	—	8,617,963		—
Reclassification	—	(22,421,146	)	—
Other	—	—		7,653
Shares outstanding at end of year	—	—		13,803,183
Class B Common Stock Outstanding:
Shares outstanding at beginning of year	—	1,513,592		1,287,696
Restricted stock grants vested	—	270,266		225,896
Reclassification	—	(1,783,858	)	—
Shares outstanding at end of year	—	—		1,513,592

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The value of the options granted was estimated at the date of grant using the Black-Scholes pricing model using the following assumptions:

Risk-free rate of return	1.26	%
Dividend yield	1.25	%
Expected share price volatility(1)	18.50	%
Expected life in years(2)	6.3 years

Share-based Compensation, Stock Options, Activity

:

	Number of Shares		Weighted-average exercise price		Weighted-average remaining years of contractual life	Aggregate intrinsic value (in thousands)
Outstanding at January 1, 2017	1,018,942		$	16.00
Granted	—		—
Forfeited	(21,122	)	16.00
Exercised	(67,380	)	16.00
Outstanding at December 31, 2017	930,440		$	16.00	8.5 years	$	26,983
Exercisable at December 31, 2017	219,063		$	16.00	8.5 years	$	6,353

Schedule of Nonvested Share Activity

The following table summarizes nonvested share-based awards under the 2016 Incentive Plan as of December 31, 2017:

	December 31, 2017
	Number of Awards		Weighted Average Grant-Date Fair Value
Nonvested awards, beginning of year	970,942		$	16.00
Granted	—		—
Vested	(239,043	)	16.00
Forfeited	(21,122	)	16.00
Nonvested awards, end of year	710,777		$	16.00