Non Purchased Loans - Investment and Interest Income Recognized on Impaired Loans (Details) - Non purchased loans and leases - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Investment and interest income recognized on impaired loans
Average Recorded Investment	$ 17,618	$ 29,234
Interest Income Recognized	189	171
Commercial, financial, agricultural
Investment and interest income recognized on impaired loans
Average Recorded Investment	2,338	2,714
Interest Income Recognized	11	39
Lease financing
Investment and interest income recognized on impaired loans
Average Recorded Investment	159	0
Interest Income Recognized	0	0
Real estate – construction
Investment and interest income recognized on impaired loans
Average Recorded Investment	150	0
Interest Income Recognized	18	0
Real estate – 1-4 family mortgage
Investment and interest income recognized on impaired loans
Average Recorded Investment	8,197	11,088
Interest Income Recognized	67	26
Real estate – commercial mortgage
Investment and interest income recognized on impaired loans
Average Recorded Investment	6,670	15,314
Interest Income Recognized	92	106
Installment loans to individuals
Investment and interest income recognized on impaired loans
Average Recorded Investment	104	118
Interest Income Recognized	$ 1	$ 0