Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Corporate tax rate		21.00%	21.00%	35.00%
Amounts related to the remeasurement of federal deferred tax assets and liabilities			$ 1,200,000
Amounts related to one-time transition tax on mandatory deemed repatriation of foreign earnings			400,000
Cumulative foreign earnings from tax cuts and jobs act of 2017			$ 22,600,000
Tax Cuts and Jobs Act of 2017, accounting complete			true
Additional income tax expense due to tax cuts and jobs act of 2017			$ 400,000
Long-term net deferred tax assets		$ 1,000,000	1,100,000
Long-term net deferred tax liabilities		22,884,000	969,000
Valuation allowance		2,274,000	2,574,000	$ 2,686,000	$ 2,193,000
Operating loss carryforwards related to a prior acquisition		3,400,000
U.S. federal and state capital loss carryforwards		5,200,000
Deferred tax assets, Capital loss carryforwards expires in 2020		600,000
Deferred tax assets, Capital loss carryforwards expires in 2021		1,400,000
Deferred tax assets, Capital loss carryforwards expires in 2022		3,200,000
Unremitted earnings of U.S. deferred tax liability of foreign subsidiaries		0
Unremitted earnings		19,200,000
Unrecognized tax benefits		345,000	$ 799,000	$ 806,000	$ 1,774,000
Income tax expense to settle a foreign tax audit		300,000
Maximum [Member] | Scenario, Forecast [Member]
Income Taxes [Line Items]
Decrease in unrecognized tax benefits	$ 300,000
U.S. Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards		$ 18,500,000
Operating loss carryforwards, limitations on use		The Act allows U.S. federal net operating loss carryforwards resulting from taxable years beginning after December 31, 2017 to be carried forward indefinitely and can be used to offset 80% of U.S. taxable income.
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards		$ 24,100,000