Summary of Significant Accounting Policies - Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net earnings	$ 2,825	$ 1,546	$ 4,709	$ 2,808	$ 5,846	$ 3,073	$ 3,503	$ (11,427)	$ 11,888	$ 995	$ 8,207
Basic weighted average number of shares outstanding (in shares)									4,283	4,240	4,228
Basic net earnings per share (in dollars per share)	$ 0.65	$ 0.36	$ 1.11	$ 0.66	$ 1.38	$ 0.72	$ 0.83	$ (2.70)	$ 2.78	$ 0.23	$ 1.94
Diluted weighted average number of shares outstanding (in shares)									4,323	4,254	4,233
Diluted earnings per share (in dollars per share)	$ 0.64	$ 0.36	$ 1.10	$ 0.66	$ 1.37	$ 0.72	$ 0.82	$ (2.69)	$ 2.75	$ 0.23	$ 1.94
Restricted stock units awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units award (in shares)									23	11	5
Performance share unit awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units award (in shares)									17	3	0