Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) branches	Mar. 31, 2018 USD ($)	Dec. 31, 2018 branches
Commitments and Contingencies Disclosure [Abstract]
Standby letters of credit, financial guarantees required to perform on	$ 0	$ 0
Standby letters of credit that expire within one year	53,000
Standby letters of credit that expire thereafter	12,700
Residential mortgage loan repurchase reserve liability	$ 1,700
Days past due of GNMA loans available for repurchase	90 days
GNMA Loans past due by 90 days, but not yet repurchased	$ 158
Number Of Stores Consolidated | branches	11		31
Number of Stores Sold | branches	4
Number Of Stores To Be Sold | branches	4
Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk, percentage	75.00%		75.00%