Summary of Significant Accounting Policies - Additional Information (Details) shares in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2017 shares	Jun. 30, 2015 shares	Dec. 31, 2021 USD ($) shareholder shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares
Summary Of Significant Accounting Policies [Line Items]
Loss on extinguishment of debt			$ 8,406,000	$ 12,036,000	$ 31,995,000
Forecast period			2 years
Historical loss experience period			1 year
OREO and other repossessed assets total			$ 2,300,000	5,100,000
Foreclosed residential real estate properties			0	1,000,000
Properties for which formal foreclosure proceedings are in process			$ 2,500,000	$ 1,900,000
Vesting percentage			8.33%
Award vesting period			1 year
Anti-dilutive common stock options and warrants (in shares) | shares			411	1,700	288
Noncumulative Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Common stock issued (in shares) | shares	4,000	4,600
Residential mortgage and home equity
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off			120 days
Automobile
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be fully charged-off			120 days
Unsecured loans at banks
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be fully charged-off			150 days
Revision of Prior Period, Reclassification, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Loss on extinguishment of debt				$ 12,000,000	$ 32,000,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Number of shareholders needed to qualify as a REIT | shareholder			100
Premises and equipment, useful life			3 years
Minimum | Commitments under commercial loans and lines of credit
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off			90 days
Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of preferred stock issued by each REIT - less than			20.00%
Premises and equipment, useful life			40 years
Maximum | Commitments under commercial loans and lines of credit
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off			120 days