Loans and Lease Finance Receivables and Allowance for Loan Losses - Schedule of Recorded Investment in, and Aging of, Past Due and Nonaccrual Loans, Excluding PCI Loans by Class of Loans (Parenthetical) (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing loans, current	$ 1,400,000	$ 2,300,000
Community Bank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	13,700,000	12,300,000
30-59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	2,100	33,000
60-89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	0	57,000
90+ Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	$ 13,500,000	$ 17,600,000