Stockholders' Equity - Additional Information (Details) - USD ($)		3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 08, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2016	Nov. 01, 2019
Class Of Stock [Line Items]
Dividends declared and paid							$ 587,000	$ 587,000
Aggregate number of shares authorized to repurchase										1,250,000
Approximate percentage of shares authorized to be repurchased			3.30%
Treasury shares		118,486		118,486			118,486
Treasury shares, at cost		$ 1,668,000		$ 1,700,000			$ 1,668,000
Cash dividend declared	$ 0.03
Dividend payable date	Oct. 06, 2020
Dividends record date	Sep. 22, 2020
Dividends declared		1,157,000	$ 1,152,000	$ 1,151,000	$ 1,148,000	$ 0
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage									7.50%
Preferred stock, liquidation preference per share									$ 1,000
Preferred stock fixed dividend close date									Dec. 30, 2021
Preferred stock redemption price per share									$ 1,000
Dividends declared and paid		$ 196,000				$ 196,000	$ 587,000	$ 587,000
Series B Preferred Stock | Three-month LIBOR
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage									5.41%