Loans and Allowance - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Loans held for sale	$ 4,469	$ 7,216
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 6,901,696	6,751,199
Real estate loans - Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of troubled debt restructured loans	91.00%
Mortgage loans with formal foreclosure proceedings	$ 1,465	2,302
Loans	1,459,189	1,476,786
Loans acquired with deteriorated credit quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	23,992	24,954
Loans acquired with deteriorated credit quality \| Commercial and consumer loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	289	315
Loans acquired with deteriorated credit quality \| Real estate loans - Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,557	$ 1,536

Financing Receivable, Modifications, Post-Modification, Loans as Percentage of Troubled Debt Restructured Loans

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- Definition

Loans and Leases Receivable

+ References

No definition available.

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- Definition

The face amount of loans that will be sold to other entities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL49126937-111524

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