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)

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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, 2019
USD ($)
Constant prepayment rates [Member] | Maximum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.200
Constant prepayment rates [Member] | Minimum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.000
Constant prepayment rates [Member] | Weighted Average [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.100
Constant default rate [Member] | Maximum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.020
Constant default rate [Member] | Minimum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.020
Constant default rate [Member] | Weighted Average [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.020
Loss severity [Member] | Maximum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.400
Loss severity [Member] | Minimum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.400
Loss severity [Member] | Weighted Average [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.400
Discount rate [Member] | Maximum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.097
Discount rate [Member] | Minimum [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.095
Discount rate [Member] | Weighted Average [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Range 0.097
Discounted cash flow [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value, Amount $ 2,204