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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Impaired loans
Unpaid Contractual Principal Balance	$ 10,329		$ 10,329		$ 9,580
Recorded Investment With Allowance	6,911		6,911		4,869
Recorded Investment With No Allowance	2,593		2,593		3,961
Total Recorded Investment	9,504		9,504		8,830
Related Allowance	315		315		537
Average Recorded Investment	9,636	$ 7,423	9,561	$ 7,550
Interest Income Recognized	43	49	141	160
Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	242,974		242,974		272,216
Recorded Investment With Allowance	73,334		73,334		78,611
Recorded Investment With No Allowance	114,780		114,780		143,643
Total Recorded Investment	188,114		188,114		222,254
Related Allowance	2,548		2,548		2,552
Average Recorded Investment	191,110	207,050	197,449	211,356
Interest Income Recognized	2,456	2,506	8,154	8,184
Commercial, financial, agricultural
Impaired loans
Unpaid Contractual Principal Balance	2,565		2,565		671
Recorded Investment With Allowance	2,495		2,495		600
Recorded Investment With No Allowance	20		20		11
Total Recorded Investment	2,515		2,515		611
Related Allowance	282		282		173
Average Recorded Investment	2,533	331	2,312	334
Interest Income Recognized	2	3	6	8
Commercial, financial, agricultural \| Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	54,354		54,354		44,403
Recorded Investment With Allowance	3,417		3,417		3,779
Recorded Investment With No Allowance	27,693		27,693		25,364
Total Recorded Investment	31,110		31,110		29,143
Related Allowance	128		128		161
Average Recorded Investment	32,150	11,705	35,304	12,117
Interest Income Recognized	283	162	1,145	579
Real estate – construction
Impaired loans
Unpaid Contractual Principal Balance	256		256		576
Recorded Investment With Allowance	256		256		576
Recorded Investment With No Allowance	0		0		0
Total Recorded Investment	256		256		576
Related Allowance	2		2		5
Average Recorded Investment	256	520	256	520
Interest Income Recognized	0	1	3	2
Real estate – construction \| Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	624		624
Recorded Investment With Allowance	0		0
Recorded Investment With No Allowance	605		605
Total Recorded Investment	605		605
Related Allowance	0		0
Average Recorded Investment	558	0	560	0
Interest Income Recognized	8	0	8	0
Real estate – 1-4 family mortgage
Impaired loans
Unpaid Contractual Principal Balance	5,982		5,982		5,787
Recorded Investment With Allowance	2,983		2,983		1,381
Recorded Investment With No Allowance	2,282		2,282		3,780
Total Recorded Investment	5,265		5,265		5,161
Related Allowance	23		23		18
Average Recorded Investment	5,364	4,817	5,468	4,907
Interest Income Recognized	30	33	96	107
Real estate – 1-4 family mortgage \| Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	45,511		45,511		53,823
Recorded Investment With Allowance	11,203		11,203		12,169
Recorded Investment With No Allowance	26,421		26,421		36,074
Total Recorded Investment	37,624		37,624		48,243
Related Allowance	350		350		488
Average Recorded Investment	38,031	51,957	38,682	53,093
Interest Income Recognized	538	621	1,699	1,941
Real estate – commercial mortgage
Impaired loans
Unpaid Contractual Principal Balance	1,172		1,172		2,266
Recorded Investment With Allowance	930		930		2,066
Recorded Investment With No Allowance	208		208		146
Total Recorded Investment	1,138		1,138		2,212
Related Allowance	6		6		338
Average Recorded Investment	1,150	1,511	1,185	1,545
Interest Income Recognized	11	12	36	43
Real estate – commercial mortgage \| Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	136,472		136,472		165,700
Recorded Investment With Allowance	58,068		58,068		62,003
Recorded Investment With No Allowance	57,714		57,714		78,435
Total Recorded Investment	115,782		115,782		140,438
Related Allowance	2,068		2,068		1,901
Average Recorded Investment	117,179	141,780	119,327	144,530
Interest Income Recognized	1,541	1,705	5,015	5,610
Installment loans to individuals
Impaired loans
Unpaid Contractual Principal Balance	354		354		280
Recorded Investment With Allowance	247		247		246
Recorded Investment With No Allowance	83		83		24
Total Recorded Investment	330		330		270
Related Allowance	2		2		3
Average Recorded Investment	333	244	340	244
Interest Income Recognized	0	0	0	0
Installment loans to individuals \| Purchased with deteriorated credit quality
Impaired loans
Unpaid Contractual Principal Balance	6,013		6,013		8,290
Recorded Investment With Allowance	646		646		660
Recorded Investment With No Allowance	2,347		2,347		3,770
Total Recorded Investment	2,993		2,993		4,430
Related Allowance	2		2		$ 2
Average Recorded Investment	3,192	1,608	3,576	1,616
Interest Income Recognized	$ 86	$ 18	$ 287	$ 54

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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