SEGMENT REPORTING - Adjusted Net Income (Parenthetical) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Equity-based compensation	$ 6,452,000	$ 12,189,000	[1]
Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Equity-based compensation	(652,000)	0
Interest income	600,000	500,000
Ocgh Units Prior to Initial Public Offering in April 2012 [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Equity-based compensation	$ 5,800,000

[1] This adjustment adds back the effect of equity-based compensation charges related to unit grants made before the Company’s initial public offering, which is excluded from adjusted net income because it is a non-cash charge that does not affect the Company's financial position.