Goodwill and Intangible Assets - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Finite-Lived Intangible Assets [Line Items]
Number of operating segments | segment	3
Amortization expense on other intangible assets	$ 10,909,000	$ 11,113,000	$ 2,942,000
Impairment of other intangible assets	0	0
First Mortgage
Finite-Lived Intangible Assets [Line Items]
Value of servicing rights	600,000	1,200,000
SBA Loans
Finite-Lived Intangible Assets [Line Items]
Value of servicing rights	2,300,000	2,100,000
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization expense on other intangible assets	10,900,000	9,700,000	$ 2,900,000
Servicing Rights | First Mortgage
Finite-Lived Intangible Assets [Line Items]
Unrealized loss on equity investments	$ 200,000	$ 700,000