Shareholders' Equity - Summary of Common and Preferred Stock (Details) - shares	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2018
Class of Stock [Line Items]
Common stock shares authorized	10,000,000	10,000,000
Common stock shares issued	5,050,000	5,050,000
Common stock shares outstanding	5,050,000	5,050,000
Preferred stock shares authorized	250,000,000	250,000,000
Preferred stock shares outstanding	500,000	500,000
Fixed-to-Floating Rate Cumulative Preferred Stock, Series A [Member]
Class of Stock [Line Items]
Preferred stock shares issued	1,000,000	1,000,000
Preferred stock shares outstanding	1,000,000	1,000,000
Fixed-to-Floating Rate Cumulative Perpetual Preferred Stock, Series B [Member]
Class of Stock [Line Items]
Preferred stock shares issued	500,000	500,000	500,000
Fixed-to-Floating Rate Cumulative Perpetual Preferred Stock, Series C [Member]
Class of Stock [Line Items]
Preferred stock shares issued	500,000	0
Preferred stock shares outstanding	500,000	0