Reverse Mortgage Loans - Additional Information (Detail) - Jun. 30, 2015	USD ($)	USD ($) Loans
Reverse Mortgage Loan Activities [Line Items]
Consolidated mortgage investment	$ 25,900,000	$ 25,900,000
Number of loans | Loans		102
Average age of a mortgage backed securities borrower		93 years
Realizable collateral value of mortgage backed securities	49,000,000	$ 49,000,000
Forecasted housing prices increase rate		2.50%
Forecasted housing prices increase rate, following year and thereafter		2.00%
Internal rate of return		17.72%
Cash payments to reverse mortgagors	6,000,000	$ 6,000,000
Decrease in income	$ 148,000
Reduction in collateral value	1.00%
Maximum [Member]
Reverse Mortgage Loan Activities [Line Items]
Net present value increase (decrease)		$ 664,000
Minimum [Member]
Reverse Mortgage Loan Activities [Line Items]
Percentage of increase decrease in home value		50.00%
Net present value increase (decrease)		$ (652,000)
Increase (decrease) in present value of IRR		(1.00%)
Zero Collateral Value [Member]
Reverse Mortgage Loan Activities [Line Items]
Internal rate of return	17.10%
Decrease in income	$ 351,000
Collateral Value Reduced by One Percent [Member]
Reverse Mortgage Loan Activities [Line Items]
Internal rate of return	17.46%