Annual report pursuant to Section 13 and 15(d)

Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail)

v3.21.1
Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2021
Mar. 31, 2020
Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]                      
Income before provision for income taxes                 $ 3,267 $ 2,312 $ (145)
Provision for income taxes                 893 440 163
Net income $ 388 $ 1,060 $ 2,744 $ (1,818) $ 576 $ 9 $ 1,205 $ 82 2,374 1,872 $ (308)
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] | Amortization of Actuarial Loss [Member]                      
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]                      
Income before provision for income taxes                 (1,066) (997)  
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] | Pension and Other Postretirement Benefits Items [Member]                      
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]                      
Income before provision for income taxes                 (1,066) (997)  
Provision for income taxes                 (238) (226)  
Net income                 $ (828) $ (771)