Purchased Loans - Impaired Loans and Average Recorded Investment and Interest Income Recognized (Details) - Purchased - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Impaired loans
Unpaid Contractual Principal Balance	$ 8,599		$ 8,599		$ 6,674
Recorded Investment With Allowance	3,587		3,587		4,538
Recorded Investment With No Allowance	4,387		4,387		1,847
Total Recorded Investment	7,974		7,974		6,385
Related Allowance	126		126		515
Average Recorded Investment	7,482	$ 35,970	7,378	$ 36,708
Interest Income Recognized	117	256	199	681
Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	299,098		299,098		340,104
Recorded Investment With Allowance	90,277		90,277		89,257
Recorded Investment With No Allowance	154,602		154,602		182,501
Total Recorded Investment	244,879		244,879		271,758
Related Allowance	1,925		1,925		2,820
Average Recorded Investment	258,209	338,176	261,367	337,288
Interest Income Recognized	3,911	3,983	10,230	11,826
Commercial, financial, agricultural
Impaired loans
Unpaid Contractual Principal Balance	459		459		732
Recorded Investment With Allowance	433		433		487
Recorded Investment With No Allowance	15		15		224
Total Recorded Investment	448		448		711
Related Allowance	66		66		310
Average Recorded Investment	413	2,387	332	2,233
Interest Income Recognized	6	28	9	48
Commercial, financial, agricultural \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	26,853		26,853		20,697
Recorded Investment With Allowance	6,770		6,770		4,555
Recorded Investment With No Allowance	10,689		10,689		7,439
Total Recorded Investment	17,459		17,459		11,994
Related Allowance	325		325		372
Average Recorded Investment	14,201	15,317	13,530	15,768
Interest Income Recognized	507	252	988	839
Real estate – construction
Impaired loans
Unpaid Contractual Principal Balance	1,837		1,837		147
Recorded Investment With Allowance	759		759		145
Recorded Investment With No Allowance	1,074		1,074		0
Total Recorded Investment	1,833		1,833		145
Related Allowance	5		5		0
Average Recorded Investment	829	1,010	741	819
Interest Income Recognized	62	26	62	28
Real estate – construction \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance					1,141
Recorded Investment With Allowance					0
Recorded Investment With No Allowance					840
Total Recorded Investment					840
Related Allowance					0
Average Recorded Investment	0	987	0	991
Interest Income Recognized	0	15	0	48
Real estate – 1-4 family mortgage
Impaired loans
Unpaid Contractual Principal Balance	5,239		5,239		3,095
Recorded Investment With Allowance	1,521		1,521		1,496
Recorded Investment With No Allowance	3,118		3,118		1,385
Total Recorded Investment	4,639		4,639		2,881
Related Allowance	46		46		43
Average Recorded Investment	5,174	18,914	5,221	19,146
Interest Income Recognized	41	114	103	309
Real estate – 1-4 family mortgage \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	71,858		71,858		86,725
Recorded Investment With Allowance	17,639		17,639		21,887
Recorded Investment With No Allowance	42,130		42,130		50,065
Total Recorded Investment	59,769		59,769		71,952
Related Allowance	614		614		841
Average Recorded Investment	67,802	92,830	68,933	93,900
Interest Income Recognized	808	1,056	2,301	3,000
Real estate – commercial mortgage
Impaired loans
Unpaid Contractual Principal Balance	897		897		2,485
Recorded Investment With Allowance	720		720		2,275
Recorded Investment With No Allowance	169		169		183
Total Recorded Investment	889		889		2,458
Related Allowance	5		5		48
Average Recorded Investment	899	13,425	915	14,271
Interest Income Recognized	8	87	25	294
Real estate – commercial mortgage \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	198,563		198,563		229,075
Recorded Investment With Allowance	65,175		65,175		62,449
Recorded Investment With No Allowance	100,791		100,791		122,538
Total Recorded Investment	165,966		165,966		184,987
Related Allowance	985		985		1,606
Average Recorded Investment	174,394	226,533	177,039	224,004
Interest Income Recognized	2,578	2,635	6,886	7,859
Installment loans to individuals
Impaired loans
Unpaid Contractual Principal Balance	167		167		215
Recorded Investment With Allowance	154		154		135
Recorded Investment With No Allowance	11		11		55
Total Recorded Investment	165		165		190
Related Allowance	4		4		114
Average Recorded Investment	167	234	169	239
Interest Income Recognized	0	1	0	2
Installment loans to individuals \| Receivables Acquired with Deteriorated Credit Quality
Impaired loans
Unpaid Contractual Principal Balance	1,824		1,824		2,466
Recorded Investment With Allowance	693		693		366
Recorded Investment With No Allowance	992		992		1,619
Total Recorded Investment	1,685		1,685		1,985
Related Allowance	1		1		$ 1
Average Recorded Investment	1,812	2,509	1,865	2,625
Interest Income Recognized	$ 18	$ 25	$ 55	$ 80

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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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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