SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Loans on Real Estate [Line Items]
Face Amount of Mortgages	$ 761,258
Carrying Amount of Mortgages	710,858	$ 671,232	$ 639,343	$ 679,795
Carrying Amount of Loans Subject to Delinquent Principal or Interest	$ 13,007
Maryland | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	13.75%
Fixed/Variable	V
Final Maturity Date	2028
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 74,928
Carrying Amount of Mortgages	$ 35,964
Michigan | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	11.31%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 4,141
Carrying Amount of Mortgages	$ 4,141
Michigan | Group 2
Mortgage Loans on Real Estate [Line Items]
Interest Rate	11.04%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 4,112
Carrying Amount of Mortgages	$ 4,112
Michigan | Group 3
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.77%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 12,113
Carrying Amount of Mortgages	$ 12,113
Michigan | Group 4
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.98%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 17,698
Carrying Amount of Mortgages	$ 17,698
Michigan | Group 5
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.90%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $126.0 of principal payable monthly with $382,127 due at maturity
Prior Liens	None
Face Amount of Mortgages	$ 415,000
Carrying Amount of Mortgages	$ 409,256
Michigan | Group 6
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.73%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $2.0 of principal payable monthly with $10,466 due at maturity
Prior Liens	None
Face Amount of Mortgages	$ 11,000
Carrying Amount of Mortgages	$ 10,961
Michigan | Group 7
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.74%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 455
Carrying Amount of Mortgages	$ 455
Michigan | Group 8
Mortgage Loans on Real Estate [Line Items]
Interest Rate	8.84%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 14,045
Carrying Amount of Mortgages	$ 14,045
Michigan | Group 9
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.50%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $8.0 of principal payable monthly with $42,364 due at maturity
Prior Liens	None
Face Amount of Mortgages	$ 44,200
Carrying Amount of Mortgages	$ 44,159
Michigan | Group 10
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.50%
Fixed/Variable	V
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 124
Carrying Amount of Mortgages	$ 124
Michigan | Group 11
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.73%
Fixed/Variable	V
Final Maturity Date	2019
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 6,518
Carrying Amount of Mortgages	$ 6,518
Michigan | Group 12
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.73%
Fixed/Variable	V
Final Maturity Date	2019
Periodic Payment Terms	Interest accrues monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 13,931
Carrying Amount of Mortgages	$ 13,931
Ohio | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.18%
Fixed/Variable	V
Final Maturity Date	2027
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 112,500
Carrying Amount of Mortgages	$ 112,500
Ohio | Group 2
Mortgage Loans on Real Estate [Line Items]
Interest Rate	12.15%
Fixed/Variable	V
Final Maturity Date	2019
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	None
Face Amount of Mortgages	$ 11,874
Carrying Amount of Mortgages	$ 11,874
Tennessee | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	8.35%
Fixed/Variable	F
Final Maturity Date	2015
Periodic Payment Terms	Past due
Prior Liens	None
Face Amount of Mortgages	$ 6,997
Carrying Amount of Mortgages	1,472
Carrying Amount of Loans Subject to Delinquent Principal or Interest	$ 1,472
Virginia | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	8.75%
Fixed/Variable	F
Final Maturity Date	2018
Periodic Payment Terms	Past due
Prior Liens	None
Face Amount of Mortgages	$ 11,622
Carrying Amount of Mortgages	11,535
Carrying Amount of Loans Subject to Delinquent Principal or Interest	$ 11,535