Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Schedule Of Significant Accounting Policies [Line Items]
Moving average period to determine market value of plan assets	5 years
Percentage rate of gains or losses recognizes in fair market value of assets	20.00%
Diluted	12,590,230	12,447,919
Operating lease ROU asset	$ 4,263	$ 0
Operating lease liability	$ 4,263
Accounting Standards Update 2016-02 [Member]
Schedule Of Significant Accounting Policies [Line Items]
Operating lease ROU asset			$ 5,893
Operating lease liability			5,893
Cumulative effect adjustment to the corporation's retained earnings			$ 0
Stock Option [Member]
Schedule Of Significant Accounting Policies [Line Items]
Weighted average outstanding stock options	671,886	904,086
Restricted Stock Units (RSUs) [Member]
Schedule Of Significant Accounting Policies [Line Items]
Vesting period, years	3 years
Stock Option [Member]
Schedule Of Significant Accounting Policies [Line Items]
Vesting period, years	3 years
Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Investments in joint ventures	20.00%
Defined benefit plan actuarial gain loss percentage	10.00%
Minimum [Member] | Land Improvements [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	15 years
Minimum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	25 years
Minimum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	3 years
Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Investments in joint ventures	50.00%
Expected disposal period of assets held for sale	1 year
Defined benefit plan actuarial gain loss percentage	10.00%
Maximum [Member] | Land Improvements [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	20 years
Maximum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	50 years
Maximum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	25 years