Loans and Allowance for Loan Losses - Loan Portfolio by Categories (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 11,860,000	$ 10,780,000
Loans acquired, net of discount and allowance	3,734,921	5,074,076
Total loans	11,858,195	10,779,685
Loans, Excluding Acquired Loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	8,123,274	5,705,609
Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	441,718	465,516
Consumer \| Credit cards
Loans and Leases Receivable Disclosure [Line Items]
Loans	182,137	185,422
Consumer \| Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans	259,581	280,094
Real estate
Loans and Leases Receivable Disclosure [Line Items]
Loans	5,709,067	4,239,612
Real estate \| Construction
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,229,888	614,155
Real estate \| Single family residential
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,401,991	1,094,633
Real estate \| Other commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	3,077,188	2,530,824
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,827,120	973,519
Commercial \| Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	1,608,342	825,217
Commercial \| Agricultural
Loans and Leases Receivable Disclosure [Line Items]
Loans	218,778	148,302
Other
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 145,369	$ 26,962

Loans acquired which are not covered by FDIC loss share agreements, net of discount.

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- Definition

Loans and leases receivable, net of deferred income covered and not covered

+ References

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- Definition

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+ References

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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