Other Real Estate Owned - Covered and Not Covered Under a Loss-Share Agreement, Net of Valuation Allowances and Direct Write-Downs (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other real estate owned ("OREO") covered and not covered under a loss-share agreement, net of valuation allowances and direct write-downs
Purchased OREO	$ 7,932	$ 11,524
Non Purchased OREO	4,665	4,410
Total OREO	12,597	15,934
Residential real estate
Other real estate owned ("OREO") covered and not covered under a loss-share agreement, net of valuation allowances and direct write-downs
Purchased OREO	501	1,683
Non Purchased OREO	1,485	758
Total OREO	1,986	2,441
Commercial real estate
Other real estate owned ("OREO") covered and not covered under a loss-share agreement, net of valuation allowances and direct write-downs
Purchased OREO	2,978	4,314
Non Purchased OREO	1,656	1,624
Total OREO	4,634	5,938
Residential land development
Other real estate owned ("OREO") covered and not covered under a loss-share agreement, net of valuation allowances and direct write-downs
Purchased OREO	706	1,100
Non Purchased OREO	575	781
Total OREO	1,281	1,881
Commercial land development
Other real estate owned ("OREO") covered and not covered under a loss-share agreement, net of valuation allowances and direct write-downs
Purchased OREO	3,747	4,427
Non Purchased OREO	949	1,247
Total OREO	$ 4,696	$ 5,674