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Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | $ 5,606,808,000 |  | $ 4,975,976,000
Percentage of loans secured by real estate | 59.00% |  |
Interest income that would have been recognized | $ 1,400,000 | $ 1,700,000 |
Interest income recognized on impaired loans | 0 | $ 0 |
Commercial and Industrial [Member] | Ancillary Services [Member] |  |  |
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | 83,000,000 |  | $ 60,000,000
Pegasus Bank [Member] |  |  |
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | 392,144,000 |  |
Pegasus Bank [Member] | Real Estate [Member] |  |  |
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | $ 209,000,000 |  |
Percentage of loans secured by real estate | 53.00% |  |
Pegasus Bank [Member] | Commercial and Industrial [Member] |  |  |
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | $ 160,000,000 |  |
Pegasus Bank [Member] | Commercial and Industrial [Member] | Oil and Gas Industry [Member] |  |  |
Financing Receivable Recorded Investment [Line Items] |  |  |
Total loans | $ 40,000,000 |  |

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- Definition Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
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- Definition Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554 + Details
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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. + 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=118952595&loc=d3e4428-111522 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524 + Details
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