Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Schedule of Fair Value Liabilities Measured On Non-Recurring Basis Valuation Techniques (Detail)

v3.20.4
Fair Value Measurements - Schedule of Fair Value Liabilities Measured On Non-Recurring Basis Valuation Techniques (Detail) - Mortgage Rights [Member] - Fair Value, Inputs, Level 3 [Member] - Fair Value, Nonrecurring [Member]
$ in Thousands
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Constant prepayment rates [Member] | Maximum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 20.0 20.0
Constant prepayment rates [Member] | Minimum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 0.0 0.0
Constant prepayment rates [Member] | Weighted Average [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 10.0 10.0
Constant default rate [Member] | Maximum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 4.1 2.0
Constant default rate [Member] | Minimum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 0.3 2.0
Constant default rate [Member] | Weighted Average [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 1.1 2.0
Loss severity [Member] | Maximum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 31.4 40.0
Loss severity [Member] | Minimum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 26.2 40.0
Loss severity [Member] | Weighted Average [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 28.0 40.0
Discount rate [Member] | Maximum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 10.0 9.7
Discount rate [Member] | Minimum [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 10.0 9.5
Discount rate [Member] | Weighted Average [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Range 10.0 9.7
Discounted cash flow [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value, Amount $ 2,135 $ 2,204