Equity-Based Compensation - Summary of Status of Equity-Based Compensation Plans (Details 4)	Dec. 31, 2017 shares
Performance Option [Member]
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	295,000
2014 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available to be granted	1,500,000
Stock options outstanding, shares	1,020,759
Restricted Stock Units, awarded and vested	176,221
RSUs outstanding, shares	725,759
Awards available to be granted	303,020
2014 Plan | Performance Option [Member]
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	295,000
2009 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available to be granted	3,400,000
Stock options outstanding, shares	122,600
RSUs outstanding, shares	122,600
Awards available to be granted	0
2009 Plan | Performance Option [Member]
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	0
2004 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available to be granted	6,500,000
Stock options outstanding, shares	57,391
RSUs outstanding, shares	57,391
Awards available to be granted	0
2004 Plan | Performance Option [Member]
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	0
Directors' Plan
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	9,620
RSUs outstanding, shares	9,620
Awards available to be granted	0
Directors' Plan | Performance Option [Member]
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding, shares	0