Receivables - Additional Information (Detail) - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Due period of notes receivable as secured by deed of trust	3 years
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal amount of loan received	$ 4,394
Interest amount of loan received	$ 49