Equity-Based Compensation - Restricted Stock (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Nonvested awards
Equity interests purchased	$ 473,000	$ 731,000
2015 Plan
Equity-based compensation
Shares authorized for issuance	7,120,000
Restricted stock
Nonvested awards
Equity interests purchased	$ 473,000
Unrecognized compensation
Unrecognized compensation costs	$ 53,600,000
Unrecognized compensation costs, weighted average period for recognition	2 years 8 months 12 days
Restricted stock | 4-year service vesting
Nonvested awards
Granted (in shares)	326,060
Restricted stock | Service vesting, year 1
Vesting terms
Vesting percentage	20.00%
Restricted stock | Service vesting, year 2
Vesting terms
Vesting percentage	20.00%
Restricted stock | Service vesting, year 3
Vesting terms
Vesting percentage	30.00%
Restricted stock | Service vesting, year 4
Vesting terms
Vesting percentage	30.00%
Restricted stock | 3-year performance vesting (cliff)
Nonvested awards
Granted (in shares)	253,299
Restricted stock | 2015 Plan
Nonvested awards
Nonvested at beginning of period (in shares)	2,255,681
Granted (in shares)	579,359
Vested (in shares)	(95,416)
Forfeited (in shares)	(18,156)
Nonvested at end of period (in shares)	2,721,468
Weighted Average Fair Value at Grant Date
Nonvested at beginning of period (in dollars per share)	$ 25.15
Granted (in dollars per share)	26.18
Vested (in dollars per share)	25.00
Forfeited (in dollars per share)	25.00
Nonvested at end of period (in dollars per share)	$ 25.38