Shareholders' Equity - Summary of Common and Preferred Stock (Details) - shares	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
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
Fixed-to-Floating Rate Cumulative Preferred Stock, Series A [Member]
Class of Stock [Line Items]
Preferred stock shares issued			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	0
Preferred stock shares outstanding	500,000		0