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Allowance for Loan Losses - Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings (Details) - Commercial - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 4,544,006 | $ 4,503,594
Total percentage of recorded investment in commercial loan | 100.00% | 100.00%
Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 4,246,345 | $ 4,302,762
Total percentage of recorded investment in commercial loan | 93.40% | 95.50%
Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 132,877 | $ 130,101
Total percentage of recorded investment in commercial loan | 3.00% | 2.90%
Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 164,784 | $ 70,731
Total percentage of recorded investment in commercial loan | 3.60% | 1.60%
Commercial real estate |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 2,788,641 | $ 2,685,994
Total percentage of recorded investment in commercial loan | 100.00% | 100.00%
Commercial real estate | Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 2,636,581 | $ 2,588,847
Total percentage of recorded investment in commercial loan | 94.50% | 96.40%
Commercial real estate | Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 74,169 | $ 66,436
Total percentage of recorded investment in commercial loan | 2.70% | 2.50%
Commercial real estate | Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 77,891 | $ 30,711
Total percentage of recorded investment in commercial loan | 2.80% | 1.10%
Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 1,455,578 | $ 1,433,266
Total percentage of recorded investment in commercial loan | 100.00% | 100.00%
Commercial and industrial | Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 1,337,331 | $ 1,345,810
Total percentage of recorded investment in commercial loan | 91.90% | 93.90%
Commercial and industrial | Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 50,142 | $ 54,320
Total percentage of recorded investment in commercial loan | 3.40% | 3.80%
Commercial and industrial | Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 68,105 | $ 33,136
Total percentage of recorded investment in commercial loan | 4.70% | 2.30%
Commercial construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 299,787 | $ 384,334
Total percentage of recorded investment in commercial loan | 100.00% | 100.00%
Commercial construction | Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 272,433 | $ 368,105
Total percentage of recorded investment in commercial loan | 90.90% | 95.80%
Commercial construction | Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 8,566 | $ 9,345
Total percentage of recorded investment in commercial loan | 2.80% | 2.40%
Commercial construction | Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans and leases receivables, recorded investment | $ 18,788 | $ 6,884
Total percentage of recorded investment in commercial loan | 6.30% | 1.80%

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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 + Details
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