Stock Option Plan - Additional Information (Detail)					12 Months Ended
	May 07, 2021 USD ($) person $ / shares shares	Dec. 31, 2020 USD ($) shares	Apr. 24, 2020 USD ($) person $ / shares shares	May 03, 2019 USD ($) person $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2004	Dec. 31, 2005 shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Deferred compensation (in shares) | shares		120,240			9,486
Exercise price of options (in usd per share) | $ / shares					$ 43.89	$ 50.00	$ 55.71
Intrinsic value of options exercised					$ 400,000	$ 100,000	$ 600,000
Intrinsic value of options exercisable		$ 2,300,000			$ 4,900,000	$ 2,300,000
Closing price (in usd per share) | $ / shares					$ 53.02
Allocated share based compensation					$ 1,300,000
Future expense					$ 1,700,000
2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares				$ 55.71
Fair value stock option grant				$ 1,900,000
2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares			$ 50.00
Closing price (in usd per share) | $ / shares			$ 28.02
Fair value stock option grant			$ 200,000
2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares	$ 43.89
Fair value stock option grant	$ 1,400,000
Common Stock
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Shares due to exercise of employee stock options and issuance of directors' deferred stock | shares					7,874
Officer | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person				23
Options vested				25.00%
Fair value stock option grant				$ 1,700,000
Officer | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person			20
Options vested			25.00%
Fair value stock option grant			$ 200,000
Officer | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person	21
Options vested	25.00%
Fair value stock option grant	$ 1,200,000
Director | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person				11
Fair value stock option grant				$ 226,600
Director | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person			11
Fair value stock option grant			$ 23,100
Director | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of individuals granted options | person	11
Fair value stock option grant	$ 173,800
Stock options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Expiration period								10 years
Stock options | Amended 2004 Plan
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Authorized shares for a grant | shares									3,400,000
Stock options | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares				260,000
Stock options | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares			238,000
Stock options | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares	250,500
Stock options | Officer
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Option vesting period								4 years
Stock options | Officer | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Option vesting period				4 years
Stock options | Officer | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Option vesting period			4 years		4 years
Stock options | Officer | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Option vesting period	4 years				4 years
Incentive stock option | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares				34,651
Incentive stock option | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares			29,624
Incentive stock option | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares	35,572
Nonqualified stock options | 2019 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares				225,349
Nonqualified stock options | 2020 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares			208,376
Nonqualified stock options | 2021 Options
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares) | shares	214,928