Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity - Additional Information (Detail)

v3.20.4
Shareholders' Equity - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Equity [Abstract]      
Preferred stock, shares outstanding 0 0  
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax $ (72) $ (141) $ 82
Common Stock, Shares, Issued 15,200,435 15,135,598  
Preferred Stock, Shares Issued 0 0  
Preferred Stock, Shares Authorized 5,000,000    
Accumulated other comprehensive loss $ (131) $ (59)  
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax 72 141 (82)
Pension and Other Postretirement Benefits Cost (Reversal of Cost) 100 100 100
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest $ (310,629) $ 70,448 $ 224,867