Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Schedule of stock option activity

	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms (Years)	Aggregate Intrinsic Value
						(in millions)
Options outstanding at December 31, 2016	60,793		$	8.12	1.9	$1.2
Granted	—		—
Exercised	(26,450	)	8.12
Cancelled	—		—
Options outstanding at December 31, 2017	34,343		$	8.12	0.9	$1.0

Schedule of restricted stock activity

	Number of Restricted Share Awards		Weighted Average Grant-Date Fair Value per Award
Restricted share awards outstanding at December 31, 2016	6,749,083		$	22.35
Granted	2,060,027		28.87
Vested	(1,840,119	)	31.09
Forfeited	(158,610	)	24.27
Restricted share awards outstanding at December 31, 2017	6,810,381		$	21.91