Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Federal statutory tax rate									21.00%	21.00%	21.00%
Provision for income taxes	$ 11,703,000	$ 7,669,000	$ 42,000	$ 3,621,000	$ 7,046,000	$ 8,334,000	$ 10,103,000	$ 8,858,000	$ 23,035,000	$ 34,341,000	$ 31,412,000
Valuation allowance of deferred tax assets	0								0
Qualifying and non-qualifying tax bad debt reserves	45,900,000				45,900,000				45,900,000	45,900,000
Provision for income taxes									0
Related amount of unrecognized deferred tax liability	10,800,000				10,800,000				10,800,000	10,800,000
Federal and state income taxes applicable to securities transactions									1,000,000.0	1,000,000.0	(200,000)
Unrecognized tax benefits and interest	324,000				$ 434,000				324,000	$ 434,000	$ 465,000	$ 467,000
Unrecognized tax benefits that would affect the effective tax rate	300,000								300,000
YCB and OLBK [Member]
Income Tax Disclosure [Line Items]
Federal deferred tax assets net operating loss carryforwards	25,700,000								$ 25,700,000
YCB and OLBK [Member] | Maryland [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards expiration date									2035
State and local deferred tax assets net operating loss carryforwards	$ 18,000,000.0								$ 18,000,000.0
Earliest Tax Year [Member]
Income Tax Disclosure [Line Items]
Earliest year for tax examination									2017
Earliest Tax Year [Member] | YCB and OLBK [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards expiration date									2033
Latest Tax Year [Member] | YCB and OLBK [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards expiration date									2036
CARES Act [Member]
Income Tax Disclosure [Line Items]
Federal statutory tax rate											21.00%
Provision for income taxes									$ (200,000)
Maximum [Member] | CARES Act [Member]
Income Tax Disclosure [Line Items]
Net operating loss period									5 years