Variable Interest Entities - Schedule of Payments Made to Entity Related to Guarantee Obligations (Detail) - CUSO RSA [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Variable Interest Entity [Line Items]
Regular Payments	$ 2,280	$ 1,158
Discharge Payments	2,709	0
Net guarantee obligation payments	$ 4,989	$ 1,158

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_VariableInterestEntityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration