Earnings per Common Share - Reconciliation of Number of Common Shares Used in Calculating Basic and Diluted Net Earnings Per Share (Detail) - $ / shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Weighted Average Number of Shares Outstanding, Basic	16,687	16,595	16,689	16,581
Weighted Average Number of Shares Outstanding, Diluted	16,971	16,783	16,689	16,689
Basic net earnings per common share (in dollars per share)	$ 0.12	$ 1.29	$ (2.25)	$ 3.29
Diluted net earnings per common share (in dollars per share)	$ 0.11	$ 1.28	$ (2.25)	$ 3.27
Anti-dilutive shares excluded from calculation	300	400	600	600
Performance Shares [Member]
Earnings Per Share [Abstract]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	98	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	98	0	0	0