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Long-Term Borrowings and Subordinated Debt - Additional Information (Details) - USD ($) | Jun. 18, 2015 | Mar. 05, 2015 | Dec. 31, 2016 | Dec. 31, 2015 | Mar. 04, 2015
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Debt Instrument [Line Items] |  |  |  |  |
Long-term borrowings |  |  | $ 14,700,000 | $ 117,000,000 |
Total loans pledged as collateral |  |  | 3,200,000,000 |  |
Maximum eligible borrowing based on qualifying collateral |  |  | 1,400,000,000.0 |  |
Maximum borrowing capacity |  |  | 2,300,000,000.0 |  |
Capital lease |  |  | $ 100,000 |  |
Percentage of equity owned |  |  | 100.00% |  |
2006 Junior Subordinated Debt | Integrity Bancshares, Inc. |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Junior subordinated debt assumed on acquisition |  |  |  |  | $ 13,500,000
Junior subordinated debt paid off | $ 5,000,000 | $ 8,500,000 |  |  |

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- Definition Amount of long-term debt due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472 + Details
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- Definition Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13,16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
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- Definition Amount of the collateral pledged in support of federal home loan bank advances outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 + Details
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- Definition Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64702-112823 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
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- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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