Mortgage Banking Activities, Components of Loans Held For Sale (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Number of days for past due for loan to be considered nonperforming (in days)	90 days		90 days
Residential mortgage loans held for sale, nonperforming	$ 0		$ 0
Credit losses recognized on residential mortgage loans held for sale	0	$ 0
Components of Residential Mortgage Loans Held for Sale [Abstract]
Unpaid principal balance	185,713		175,117
Residential mortgage loans held for sale, Fair value	191,860		177,703
Residential mortgage loans held for sale	$ 204,720		$ 182,271
Residential Mortgage Loan Commitments [Member] | Not Designated as Hedging Instrument [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days outstanding for residential mortgage commitments, minimum (in days)	60 days		60 days
General number of days outstanding for residential mortgage commitments, maximum (in days)	90 days		90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Derivative, Notional Amount	$ 657,570		$ 158,460
Derivative, Net fair value	$ 24,250		$ 5,233
Forward sales contracts [Member] | Not Designated as Hedging Instrument [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days for delivery of loans, for which the price is set by forward sales contracts, minimum (in days)	60 days		60 days
General number of days for delivery for loans, for which the price is set by forward sales contracts, maximum (in days)	90 days		90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Derivative, Notional Amount	$ 750,719		$ 315,203
Derivative, Net fair value	$ (11,390)		$ (665)