Summary of Significant Accounting Policies - Additional Information (Detail) (RMCO, LLC)	Mar. 31, 2015	Dec. 31, 2014	Oct. 07, 2013
RMCO, LLC
Significant Accounting Policies [Line Items]
Percentage of common membership units in subsidiaries	40.42%	39.89%	39.56%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant