Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Impact of Modifications Classified as Troubled Debt Restructurings (Details) - Troubled Debt Restructurings [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) Contract	Mar. 31, 2018 USD ($) Contract
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	10	5
Pre-Modification Outstanding Recorded Investment	$ 9,170	$ 2,589
Post-Modification Outstanding Recorded Investment	$ 9,170	$ 2,589
Secured by 1-4 Family Residential Properties [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	2	4
Pre-Modification Outstanding Recorded Investment	$ 86	$ 118
Post-Modification Outstanding Recorded Investment	$ 86	$ 118
Commercial and Industrial Loans [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	6	1
Pre-Modification Outstanding Recorded Investment	$ 9,054	$ 2,471
Post-Modification Outstanding Recorded Investment	$ 9,054	$ 2,471
Consumer Loans [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	2
Pre-Modification Outstanding Recorded Investment	$ 30
Post-Modification Outstanding Recorded Investment	$ 30