Loans and Leases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases receivable, net of deferred income, acquired	$ 377,376		$ 246,333	$ 377,376
Carrying amount	695		264	695
Charge-offs			3,463	15,651	$ 7,137
Loans and leases held for investment	4,006,574		4,386,836	4,006,574
Recoveries			912	3,150	1,301
Impaired loans with no related reserve, recorded investment	13,174		23,486	13,174
Impaired loans, related allowance	1,415		2,108	1,415
Receivable related to an operating lease contract	0		54	0
Interest income on lease financings			8,100	7,500
Minimum [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount of loan relationship balance, loans reviewed annually			1,000
Maximum [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount of loan relationship balance, loans reviewed on a performance basis			1,000
Fox Chase Bank [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases receivable, net of deferred income, acquired			223,000
Carrying amount			58
Valley Green Bank [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases receivable, net of deferred income, acquired			23,300
Carrying amount			206
Commercial, Financial and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases receivable, net of deferred income, acquired	24,519		7,465	24,519
Charge-offs			1,965	14,655	1,030
Loans and leases held for investment	937,685		947,029	937,685
Recoveries			367	2,140	801
Impaired loans with no related reserve, recorded investment	2,776		3,055	2,776
Impaired loans, related allowance	413		44	413
Lease Financings [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases receivable, net of deferred income, acquired	0		0	0
Charge-offs			427	572	3,992
Loans and leases held for investment	141,956		149,421	141,956
Recoveries			244	231	$ 206
Impaired loans with no related reserve, recorded investment	0		277	0
Impaired loans, related allowance	0		$ 0	0
Loan Participations [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Charge-offs		$ 12,700
Loans and leases held for investment	13,000			13,000
Total participating interest from all parties	80,000			80,000
Recoveries	$ 1,800
Allowance for loan and lease losses write-offs, net				$ 10,900