Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Troubled Debt Restructuring Subsequently Defaulted (Details) - Troubled Debt Restructurings that Subsequently Defaulted [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($) Contract	Sep. 30, 2017 USD ($) Contract
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	13	6
Recorded Investment | $	$ 14,327	$ 64
Construction, Land Development and Other Land [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	1	0
Recorded Investment | $	$ 21	$ 0
Secured by 1-4 Family Residential Properties [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	6	4
Recorded Investment | $	$ 321	$ 64
Commercial and Industrial Loans [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	6	2
Recorded Investment | $	$ 13,985	$ 0