Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Troubled Debt Restructuring Subsequently Defaulted (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) Contract	Mar. 31, 2018 USD ($) Contract
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	0	0
Recorded Investment | $	$ 0	$ 0
Troubled Debt Restructurings that Subsequently Defaulted [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	12	3
Recorded Investment | $	$ 15,912	$ 4
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Construction, Land Development and Other Land [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	1	0
Recorded Investment | $	$ 22	$ 0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Secured by 1-4 Family Residential Properties [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	3	1
Recorded Investment | $	$ 684	$ 4
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Commercial and Industrial Loans [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	6	2
Recorded Investment | $	$ 15,178	$ 0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Consumer Loans [Member]
Troubled Debt Restructurings [Abstract]
Number of Contracts | Contract	2	0
Recorded Investment | $	$ 28	$ 0