Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Effective income tax rates on continuing operations	15.50%	14.80%	12.20%
Effective income tax rates from discontinued operations			18.50%
Statutory federal tax rate	21.00%
State net operating loss carry forwards	$ 1,100
Change in valuation allowance, unrealized deferred tax assets	2,200
Gross amount of unrecognized tax benefits	6,717	$ 5,802	$ 4,859
Total amount of unrecognized tax benefits, net of associated deferred tax benefit that would impact effective tax rate, if recognized	$ 5,300	$ 4,600
Minimum [Member]
Income Taxes [Line Items]
State net operating loss carry forwards, expiration year	2020
Maximum [Member]
Income Taxes [Line Items]
State net operating loss carry forwards, expiration year	2040