Stockholders' Equity - Issuance of Common Stock (Details) $ in Thousands					12 Months Ended
	Jul. 01, 2019 director shares	Jul. 02, 2018 director shares	Mar. 15, 2018 employee shares	Jul. 03, 2017 director shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) employee shares	May 20, 2019 USD ($)	May 23, 2018 USD ($)	Dec. 31, 2017	May 25, 2017 USD ($)
Share-based compensation
Stock compensation expense before tax benefit					$ 45	$ 77	$ 71
Directors | Restricted Stock
Share-based compensation
Fair value of equity grant award approved for each director								$ 50	$ 50		$ 50
Number of restricted stock awards granted | shares	5,708	2,778		5,334	0	5,708	2,778
Number of directors granted restricted stock awards | director	2	1		2
Number of directors who elected to receive cash in lieu of the stock | director	2	3		4
Stock compensation expense before tax benefit					$ 100	$ 100	$ 100
Officers | Restricted Stock
Share-based compensation
Number of restricted stock awards granted | shares							9,956
Issuance of common stock for officer compensation, net of tax withholding | shares			9,956
Number of directors granted restricted stock awards | employee			4
Percentage of total discretionary cash incentive award elected to be received in shares of Company stock										50.00%
Number of grantees who elected to receive a portion of total discretionary cash incentive award in shares of company stock | employee							4
Stock compensation expense before tax benefit							$ 200