Business and Organization - Additional Information (Detail) (USD $)	0 Months Ended
	Oct. 07, 2013	Mar. 31, 2015	Dec. 31, 2014
RMCO, LLC
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Percentage of common membership units in subsidiaries	39.56%	40.42%	39.89%
Common Class A | IPO
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock issued at initial public offering	11,500,000
Common stock at public offering price per share	$ 22.00