Loans and Leases - Outstanding Principal Balance and Carrying Amount of Loans and Included in Consolidated Balance Sheet (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 769,414
Carrying amount	535,596
Commercial, Financial, Leasing, etc. [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	21,114
Commercial Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	94,890
One-to-Four Family Residential [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	341,807
Consumer [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	$ 77,785