Non Purchased Loans - Narrative (Details)	2 Months Ended	3 Months Ended
	Apr. 30, 2020 USD ($) loan	Mar. 31, 2020 USD ($) loan	Mar. 31, 2019 USD ($) loan	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Allowance for loan losses attributable to restructured loans		$ 120,185,000	$ 49,835,000	$ 52,162,000	$ 49,026,000
Non purchased loans and leases
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Mortgage and commercial loans discontinued past due period		90 days
Consumer and other retail loans charged-off past due period		120 days
Interest income		$ 21,000
Troubled debt restructured		$ 0
Nonperforming loans charged-off past due period		90 days
Number of restructured loans | loan		2	0
Restructured loans discontinued past due period		90 days	90 days
Remaining availability under commitments to lend additional funds on restructured loans		$ 0	$ 44,000
Deferral period		90 days
Number of loan modifications | loan		5
Modified loans, balance		$ 1,345,000
Non purchased loans and leases | Subsequent Event
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Number of loan modifications | loan	2,900
Modified loans, balance	$ 1,285,000,000
Non purchased loans and leases | Nonaccruing Loans
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Outstanding balance of restructured loans		164,000
Non purchased loans and leases | Restructured loans
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Outstanding balance of restructured loans		2,596,000	2,976,000
Allowance for loan losses attributable to restructured loans		$ 193,000	$ 32,000