Purchased Loans - Impaired Loans and Average Recorded Investment and Interest Income Recognized (Details) - Purchased - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Impaired loans
Unpaid Contractual Principal Balance	$ 7,378		$ 7,378		$ 9,203
Recorded Investment With Allowance	2,563		2,563		2,892
Recorded Investment With No Allowance	4,131		4,131		5,672
Total Recorded Investment	6,694		6,694		8,564
Related Allowance	122		122		107
Average Recorded Investment	7,224	$ 7,836	7,361	$ 7,684
Interest Income Recognized	49	78	110	116
Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	246,550		246,550		277,709
Recorded Investment With Allowance	82,179		82,179		87,484
Recorded Investment With No Allowance	118,862		118,862		139,776
Total Recorded Investment	201,041		201,041		227,260
Related Allowance	2,256		2,256		1,777
Average Recorded Investment	231,812	270,769	233,943	272,564
Interest Income Recognized	2,790	3,199	5,678	6,501
Commercial, financial, agricultural
Impaired loans
Unpaid Contractual Principal Balance	439		439		757
Recorded Investment With Allowance	329		329		625
Recorded Investment With No Allowance	49		49		74
Total Recorded Investment	378		378		699
Related Allowance	41		41		52
Average Recorded Investment	380	342	383	347
Interest Income Recognized	3	1	6	3
Commercial, financial, agricultural \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	18,239		18,239		24,179
Recorded Investment With Allowance	3,845		3,845		5,768
Recorded Investment With No Allowance	6,570		6,570		9,547
Total Recorded Investment	10,415		10,415		15,315
Related Allowance	325		325		312
Average Recorded Investment	12,815	14,894	13,051	14,048
Interest Income Recognized	192	252	417	487
Real estate – construction
Impaired loans
Unpaid Contractual Principal Balance					1,207
Recorded Investment With Allowance					0
Recorded Investment With No Allowance					1,199
Total Recorded Investment					1,199
Related Allowance					0
Real estate – 1-4 family mortgage
Impaired loans
Unpaid Contractual Principal Balance	5,225		5,225		6,173
Recorded Investment With Allowance	700		700		1,385
Recorded Investment With No Allowance	3,926		3,926		4,225
Total Recorded Investment	4,626		4,626		5,610
Related Allowance	12		12		45
Average Recorded Investment	5,135	4,960	5,252	5,032
Interest Income Recognized	34	47	74	62
Real estate – 1-4 family mortgage \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	56,339		56,339		65,049
Recorded Investment With Allowance	14,254		14,254		15,910
Recorded Investment With No Allowance	32,122		32,122		38,059
Total Recorded Investment	46,376		46,376		53,969
Related Allowance	528		528		572
Average Recorded Investment	54,634	72,933	55,293	73,656
Interest Income Recognized	647	759	1,320	1,582
Real estate – commercial mortgage
Impaired loans
Unpaid Contractual Principal Balance	1,466		1,466		901
Recorded Investment With Allowance	1,287		1,287		728
Recorded Investment With No Allowance	156		156		165
Total Recorded Investment	1,443		1,443		893
Related Allowance	66		66		6
Average Recorded Investment	1,462	2,515	1,479	2,284
Interest Income Recognized	12	30	30	51
Real estate – commercial mortgage \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	170,327		170,327		186,720
Recorded Investment With Allowance	63,365		63,365		65,108
Recorded Investment With No Allowance	79,328		79,328		91,230
Total Recorded Investment	142,693		142,693		156,338
Related Allowance	1,400		1,400		892
Average Recorded Investment	162,712	181,007	163,959	182,894
Interest Income Recognized	1,933	2,169	3,905	4,394
Installment loans to individuals
Impaired loans
Unpaid Contractual Principal Balance	248		248		165
Recorded Investment With Allowance	247		247		154
Recorded Investment With No Allowance	0		0		9
Total Recorded Investment	247		247		163
Related Allowance	3		3		4
Average Recorded Investment	247	19	247	21
Interest Income Recognized	0	0	0	0
Installment loans to individuals \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	1,645		1,645		1,761
Recorded Investment With Allowance	715		715		698
Recorded Investment With No Allowance	842		842		940
Total Recorded Investment	1,557		1,557		1,638
Related Allowance	3		3		$ 1
Average Recorded Investment	1,651	1,935	1,640	1,966
Interest Income Recognized	$ 18	$ 19	$ 36	$ 38

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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