Non-controlling Interest - Narrative (Details) - USD ($)	1 Months Ended		6 Months Ended
	Sep. 30, 2015	Apr. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Exercise of stock options, Shares			559,068
Other distributions, non-controlling unitholders		$ 34,242,000	$ 0	$ 2,216,000
Other distributions, non-controlling unitholders, dividends			31,036,000
Other distributions, non-controlling unitholders, discretionary			3,206,000
Distributions for taxes, non-controlling unitholders			115,000	12,221,000
Liability representing the payments due pursuant to tax receivable agreements			67,418,000
Current portion of payable pursuant to tax receivable agreements			3,914,000		$ 3,914,000
Amounts paid pursuant to Tax Receivable Agreements (TRAs)			$ 0	$ 0
Quarterly distribution | Subsequent Event
Significant Accounting Policies [Line Items]
Distributions declared to non-controlling unitholders	$ 2,217,000
RMCO, LLC
Significant Accounting Policies [Line Items]
Minority economic interest in RMCO (as a percent)			41.01%		39.89%
Non-controlling unitholders ownership of common units in RMCO as a percentage			58.99%		60.11%
RMCO, LLC | RIHI Member
Significant Accounting Policies [Line Items]
Non-controlling unitholders ownership of common units in RMCO as a percentage			58.99%		60.11%
Class A common stock
Significant Accounting Policies [Line Items]
Exercise of stock options, Shares			559,068
Stock granted, net, shares			2,001