Amount of allowance for acquired non-covered loans due to reclassification.

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For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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Loans Acquired - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Loans Acquired - Textual (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Oct. 19, 2017	May 15, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 11,365,895		$ 11,365,895		$ 10,779,685
Allowance on loans acquired	2,044		2,044
Provision for loan losses	9,033	$ 7,023	18,183	$ 11,330
Loans acquired, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,232,434		4,232,434		5,074,076
Allowance on loans acquired					418
Provision for loan losses	$ 1,769	714	$ 1,837	1,464
OKSB Merger
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans					1,985,000
Gross value of loans acquired					2,021,000	$ 1,996,453
Loans acquired discount					36,300
OKSB Merger \| Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans					11,400
Gross value of loans acquired					18,100
Loans acquired discount					6,700
First Texas Merger
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans					2,208,000
Gross value of loans acquired					2,246,000	$ 2,208,378
Loans acquired discount					$ 37,800
Hardeman County Investment Company, Inc.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		249,200		249,200
Gross value of loans acquired		254,200		254,200			$ 251,649
Loans acquired discount		5,000		5,000
Hardeman County Investment Company, Inc. \| Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,400		2,400
Gross value of loans acquired		3,400		3,400
Loans acquired discount		$ 990		$ 990