Disclosure About Fair Values of Financial Instruments - Summary of Significant Unobservable Inputs Used in Level 3 Fair Value Measurements for Financial Assets Measured at Fair Value On a Nonrecurring Basis (Details) - Level 3 $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Minimum Guaranteed Proceeds Per Settlement Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs			Minimum guaranteed proceeds per Settlement Agreement
Range/Weighted Average	[1]		0.00%
Discount of Fair Value | Individually Evaluated, Net of Allocated Allowance for Credit Losses
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	[2]	Discount to fair value	Discount to fair value
Discount of Fair Value | Individually Evaluated, Net of Allocated Allowance for Credit Losses | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	[2]	0.00%	0.00%
Discount of Fair Value | Individually Evaluated, Net of Allocated Allowance for Credit Losses | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	[2]	50.00%	50.00%
Discount of Fair Value | Individually Evaluated, Net of Allocated Allowance for Credit Losses | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs, discount rate	[2],[3]	0.38
Discount of Fair Value | Individually Evaluated, Net of Allocated Allowance for Credit Losses | Fair Value, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	[2]	$ 128,519	$ 101,561
Discount of Fair Value | Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Discount to fair value	Discount to fair value
Discount of Fair Value | Other | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average		0.00%	0.00%
Discount of Fair Value | Other | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average		20.00%	20.00%
Discount of Fair Value | Other | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	[3]	10.00%
Discount of Fair Value | Other | Fair Value, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value		$ 1,008	$ 1,628
Discounted Cash Flow
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Discount rate	Discount rate 5.8%
Range/Weighted Average	[1]		0.00%
Discounted Cash Flow | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average		3.75%
Discounted Cash Flow | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average		5.80%
Discounted Cash Flow | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value	[3]	4.70%
Discounted Cash Flow | Measurement Input, Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs, discount rate			0.058
Enterprise Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs			Exit and earnings multiples, discounted cash flows, and market comparables
Enterprise Value | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value	[1]		0.00%
Enterprise Value | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value	[1]		46.00%
Enterprise Value | Comparables and Average Multiplier
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Comparables and average multiplier
Enterprise Value | Comparables and Average Multiplier | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value		5.00%
Enterprise Value | Comparables and Average Multiplier | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value		6.60%
Enterprise Value | Comparables and Average Multiplier | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value	[3]	5.33%
Enterprise Value | Discount Rates and Comparables
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Discount rates and comparables
Enterprise Value | Discount Rates and Comparables | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value		6.40%
Enterprise Value | Discount Rates and Comparables | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value		16.00%
Enterprise Value | Discount Rates and Comparables | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements, percentage of enterprise value	[3]	12.00%
Net Recoverable Oil And Gas Reserves And Forward Looking Commodity Prices
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Capitalization rate and discount rate
Net Recoverable Oil And Gas Reserves And Forward Looking Commodity Prices | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	[3]	18.00%
Estimated Closing Costs
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs		Estimated closing costs	Estimated closing costs
Range/Weighted Average		10.00%	10.00%
Estimated Closing Costs | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	[3]	10.00%

[1] Represents difference of remaining balance to fair value.

[2] Prior to the adoption of CECL on January 1, 2020, these loans were known as Impaired loans, net of specific allowance.

[3] Weighted averages were calculated using the input attribute and the outstanding balance of the loan