SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Mortgage Loans on Real Estate [Line Items]
Face Amount of Mortgages	$ 964,579,000
Carrying Amount of Mortgages	835,086,000	$ 885,313,000	$ 773,563,000	$ 710,858,000
Carrying Amount of Loans Subject to Delinquent Principal or Interest	58,122,000
Allowance for credit loss on mortgage loans	$ (21,585,000)
Michigan | Group 1
Mortgage Loans on Real Estate [Line Items]
Interest Rate	11.13%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $166.0 of principal payable monthly with $352,454 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	415,000,000
Carrying Amount of Mortgages	372,789,000
Mortgage loans on real estate periodic payment, amount	166,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 352,454,000
Michigan | Group 2
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.18%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $12.0 of principal payable monthly with $42,341 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	44,200,000
Carrying Amount of Mortgages	43,808,000
Mortgage loans on real estate periodic payment, amount	12,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 42,341,000
Michigan | Group 3
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.40%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $3.0 of principal payable monthly with $10,460 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	11,000,000
Carrying Amount of Mortgages	10,864,000
Mortgage loans on real estate periodic payment, amount	3,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 10,460,000
Michigan | Group 9
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.38%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	14,045,000
Carrying Amount of Mortgages	$ 14,045,000
Michigan | Group 10
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.40%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $4.0 of principal payable monthly with $17,613 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	18,147,000
Carrying Amount of Mortgages	18,075,000
Mortgage loans on real estate periodic payment, amount	4,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 17,613,000
Michigan | Group 12
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.52%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $15.0 of principal payable monthly with $81,302 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	83,454,000
Carrying Amount of Mortgages	83,208,000
Mortgage loans on real estate periodic payment, amount	15,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 81,302,000
Michigan | Group 13
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.40%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest plus approximately $2.9 of principal payable monthly with $16,617 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	17,032,000
Carrying Amount of Mortgages	16,983,000
Mortgage loans on real estate periodic payment, amount	2,900
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 16,617,000
Michigan | Group 14
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.49%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	465,000
Carrying Amount of Mortgages	$ 455,000
Michigan | Group 15
Mortgage Loans on Real Estate [Line Items]
Interest Rate	12.18%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	4,220,000
Carrying Amount of Mortgages	$ 4,220,000
Michigan | Group 16
Mortgage Loans on Real Estate [Line Items]
Interest Rate	11.89%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	4,120,000
Carrying Amount of Mortgages	$ 4,112,000
Michigan | Group 17
Mortgage Loans on Real Estate [Line Items]
Interest Rate	11.60%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	9,645,000
Carrying Amount of Mortgages	$ 9,374,000
Michigan | Group 18
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.75%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	26,190,000
Carrying Amount of Mortgages	$ 25,668,000
Michigan | Group 19
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.18%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	500,000
Carrying Amount of Mortgages	$ 500,000
Michigan | Group 20
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.98%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	5,450,000
Carrying Amount of Mortgages	$ 5,123,000
Michigan | Group 21
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.36%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	2,900,000
Carrying Amount of Mortgages	$ 2,542,000
Michigan | Group 22
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.74%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	9,067,000
Carrying Amount of Mortgages	$ 7,949,000
Michigan | Group 23
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.49%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	3,025,000
Carrying Amount of Mortgages	$ 3,025,000
Michigan | Group 24
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.50%
Fixed/Variable	F(2)
Final Maturity Date	2029
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	325,000
Carrying Amount of Mortgages	$ 169,000
Michigan | Group 25
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.50%
Fixed/Variable	F(2)
Final Maturity Date	2023
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	9,330,000
Carrying Amount of Mortgages	$ 9,330,000
Ohio And Pennsylvania | Group 5
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.81%
Fixed/Variable	F(2)
Final Maturity Date	2027
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	103,762,000
Carrying Amount of Mortgages	56,650,000
Carrying Amount of Loans Subject to Delinquent Principal or Interest	$ 56,650,000
Ohio | Group 4
Mortgage Loans on Real Estate [Line Items]
Interest Rate	10.50%
Fixed/Variable	F(2)
Final Maturity Date	2032
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	72,420,000
Carrying Amount of Mortgages	$ 72,420,000
Ohio | Group 11
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.50%
Fixed/Variable	F
Final Maturity Date	2022
Periodic Payment Terms	Interest payable monthly until maturity
Prior Liens	$ 0
Face Amount of Mortgages	21,325,000
Carrying Amount of Mortgages	$ 21,325,000
Texas | Group 6
Mortgage Loans on Real Estate [Line Items]
Interest Rate	7.85%
Fixed/Variable	F
Final Maturity Date	2025
Periodic Payment Terms	Interest plus approximately $139.0 of principal payable monthly with $59,749 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	72,960,000
Carrying Amount of Mortgages	65,475,000
Mortgage loans on real estate periodic payment, amount	139,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 59,749,000
Massachusetts | Group 7
Mortgage Loans on Real Estate [Line Items]
Interest Rate	9.00%
Fixed/Variable	F
Final Maturity Date	2023
Periodic Payment Terms	Interest plus approximately $55.0 of principal payable monthly with $6,079 due at maturity
Prior Liens	$ 0
Face Amount of Mortgages	9,000,000
Carrying Amount of Mortgages	7,090,000
Mortgage loans on real estate periodic payment, amount	55,000.0
Mortgage loans on real estate, periodic payment terms, balloon payment to be received	$ 6,079,000
Tennessee | Group 8
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	$ 0
Face Amount of Mortgages	6,997,000
Carrying Amount of Mortgages	1,472,000
Carrying Amount of Loans Subject to Delinquent Principal or Interest	$ 1,472,000