Loans and Allowance for Loan Losses - Aggregated analysis of the changes in allowance for loan losses - (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in allowance for loan losses
Balance at beginning of period	$ 40,355	$ 37,796	$ 41,904
Loans charged-off	(6,779)	(6,889)	(8,967)
Recoveries of loans previously charged off	3,430	3,551	3,188
Net charge-offs	(3,349)	(3,338)	(5,779)
Provision (benefit)	11,890	6,796	5,078
Benefits attributable to FDIC loss share agreements		23	786
Total provision for loan losses charged to operations	11,890	6,819	5,864
Provision for loan losses recorded through the FDIC loss share receivable		(23)	(786)
Reduction due to loan removals	(821)	(899)	(3,407)
Balance at end of period	48,075	40,355	37,796
Non-acquired loans
Changes in allowance for loan losses
Balance at beginning of period	36,960	34,090	34,539
Loans charged-off	(5,149)	(5,902)	(6,180)
Recoveries of loans previously charged off	2,953	3,233	2,801
Net charge-offs	(2,196)	(2,669)	(3,379)
Provision (benefit)	8,684	5,539	2,930
Total provision for loan losses charged to operations	8,684	5,539	2,930
Balance at end of period	43,448	36,960	34,090
Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(1,630)	(987)	(2,787)
Recoveries of loans previously charged off	477	318	387
Net charge-offs	(1,153)	(669)	(2,400)
Provision (benefit)	1,153	669	2,400
Total provision for loan losses charged to operations	1,153	669	2,400
Acquired credit impaired loans
Changes in allowance for loan losses
Balance at beginning of period	3,395	3,706	7,365
Provision (benefit)	2,053	588	(252)
Benefits attributable to FDIC loss share agreements		23	786
Total provision for loan losses charged to operations	2,053	611	534
Provision for loan losses recorded through the FDIC loss share receivable		(23)	(786)
Reduction due to loan removals	(821)	(899)	(3,407)
Balance at end of period	4,627	3,395	3,706
Residential real estate \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)	1,662	(129)	99
Benefits attributable to FDIC loss share agreements		23	228
Total provision for loan losses charged to operations	1,662	(106)	327
Provision for loan losses recorded through the FDIC loss share receivable		(23)	(228)
Reduction due to loan removals	(528)	(438)	(1,500)
Commercial owner occupied real estate loan \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off		(118)	(851)
Recoveries of loans previously charged off	220	54	31
Total provision for loan losses charged to operations	(114)	(255)	746
Consumer real estate \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)	(83)	533	336
Benefits attributable to FDIC loss share agreements			(107)
Total provision for loan losses charged to operations	(83)	533	229
Provision for loan losses recorded through the FDIC loss share receivable			107
Reduction due to loan removals	(14)	(288)	(298)
Commercial and industrial \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(776)	(876)	(357)
Recoveries of loans previously charged off	343	292	844
Total provision for loan losses charged to operations	1,079	1,452	(74)
Commercial and industrial \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(71)	(66)	(118)
Recoveries of loans previously charged off	6	9	19
Total provision for loan losses charged to operations	65	57	99
Commercial and industrial \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)	64	183	(118)
Benefits attributable to FDIC loss share agreements			131
Total provision for loan losses charged to operations	64	183	13
Provision for loan losses recorded through the FDIC loss share receivable			(131)
Reduction due to loan removals	(157)	(119)	(426)
Other income producing property \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(51)	(7)	(102)
Recoveries of loans previously charged off	85	87	85
Total provision for loan losses charged to operations	(201)	(501)	(252)
Other income producing property \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off			(4)
Recoveries of loans previously charged off	8	43	4
Total provision for loan losses charged to operations	(8)	(43)
Consumer \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(3,261)	(3,597)	(3,574)
Recoveries of loans previously charged off	689	943	1,011
Total provision for loan losses charged to operations	3,010	3,310	2,890
Consumer \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(468)	(532)	(643)
Recoveries of loans previously charged off	23	51	21
Total provision for loan losses charged to operations	445	481	622
Single pay loans \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)			(2)
Benefits attributable to FDIC loss share agreements			1
Total provision for loan losses charged to operations			(1)
Provision for loan losses recorded through the FDIC loss share receivable			(1)
Reduction due to loan removals			(68)
Other loans \| Non-acquired loans
Changes in allowance for loan losses
Total provision for loan losses charged to operations	203	(191)	(156)
Construction and land development \| Commercial non-owner occupied real estate \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(546)	(159)	(219)
Recoveries of loans previously charged off	968	912	376
Total provision for loan losses charged to operations	1,408	(778)	(1,707)
Construction and land development \| Commercial non-owner occupied real estate \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)	163		(68)
Benefits attributable to FDIC loss share agreements			74
Total provision for loan losses charged to operations	163		6
Provision for loan losses recorded through the FDIC loss share receivable			(74)
Reduction due to loan removals	(122)	(38)	(91)
Construction and land development \| Commercial \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(82)
Recoveries of loans previously charged off	4	4	4
Total provision for loan losses charged to operations	78	(4)	(4)
Other commercial non-owner occupied real estate \| Commercial non-owner occupied real estate \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off		(111)	(156)
Recoveries of loans previously charged off	132	512	67
Total provision for loan losses charged to operations	1,413	1,011	503
Other commercial non-owner occupied real estate \| Commercial non-owner occupied real estate \| Acquired credit impaired loans
Changes in allowance for loan losses
Provision (benefit)	247	1	(499)
Benefits attributable to FDIC loss share agreements			459
Total provision for loan losses charged to operations	247	1	(40)
Provision for loan losses recorded through the FDIC loss share receivable			(459)
Reduction due to loan removals		(16)	(1,024)
Other commercial non-owner occupied real estate \| Commercial \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Recoveries of loans previously charged off	2
Total provision for loan losses charged to operations	(2)	(39)
Home equity loans \| Consumer real estate \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(330)	(808)	(547)
Recoveries of loans previously charged off	210	299	244
Total provision for loan losses charged to operations	159	791	403
Home equity loans \| Consumer real estate \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(859)	(428)	(1,662)
Recoveries of loans previously charged off	393	199	237
Total provision for loan losses charged to operations	466	229	1,425
Consumer Owner Occupied Loans \| Consumer real estate \| Non-acquired loans
Changes in allowance for loan losses
Loans charged-off	(185)	(226)	(374)
Recoveries of loans previously charged off	306	134	143
Total provision for loan losses charged to operations	1,727	700	577
Consumer Owner Occupied Loans \| Consumer real estate \| Acquired non-credit impaired loans
Changes in allowance for loan losses
Loans charged-off	(150)		(360)
Recoveries of loans previously charged off	41	12	102
Total provision for loan losses charged to operations	$ 109	$ (12)	$ 258

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Provision for loan losses recorded through the FDIC loss share receivable - Amount of reduction in the reserve for loans impairments as a result of current information and events which result in it being probable that estimated cash flows will be significantly higher than previously expected or because actual cash flows are significantly greater than cash flows previously expected for loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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No definition available.

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Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, typically because they are considered to be not salvageable or have been purchased by unconsolidated collection entities. This amount is net of reduction in bad debt expense attributable to collections of loans and lease receivables which had previously been fully or partially charged off as bad debts.

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- Definition

The sum of the periodic provision charged to earnings before adjustment for amounts covered under loss sharing agreement.

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No definition available.

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A valuation allowance for financing receivables that are expected to be uncollectible.

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The increase (decrease) in the allowance for credit losses related to financing receivables.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of direct write-downs of financing receivables charged against the allowance.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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