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Allowance for Credit Losses - Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings (Details) - Commercial $ in Thousands	Dec. 31, 2019 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 5,512,796
Total percentage of recorded investment in commercial loan	100.00%
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 5,254,076
Total percentage of recorded investment in commercial loan	95.30%
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 103,878
Total percentage of recorded investment in commercial loan	1.90%
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 152,651
Total percentage of recorded investment in commercial loan	2.80%
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 2,191
Total percentage of recorded investment in commercial loan	0.00%
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 3,416,518
Total percentage of recorded investment in commercial loan	100.00%
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 3,270,437
Total percentage of recorded investment in commercial loan	95.70%
Commercial real estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 57,285
Total percentage of recorded investment in commercial loan	1.70%
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 86,772
Total percentage of recorded investment in commercial loan	2.50%
Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 2,023
Total percentage of recorded investment in commercial loan	0.00%
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 1,720,833
Total percentage of recorded investment in commercial loan	100.00%
Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 1,636,314
Total percentage of recorded investment in commercial loan	93.40%
Commercial and industrial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 36,484
Total percentage of recorded investment in commercial loan	1.70%
Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 47,980
Total percentage of recorded investment in commercial loan	4.90%
Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 55
Total percentage of recorded investment in commercial loan	0.00%
Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 375,445
Total percentage of recorded investment in commercial loan	100.00%
Commercial construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 347,324
Total percentage of recorded investment in commercial loan	92.50%
Commercial construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 10,109
Total percentage of recorded investment in commercial loan	2.70%
Commercial construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 17,899
Total percentage of recorded investment in commercial loan	4.80%
Commercial construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 133
Total percentage of recorded investment in commercial loan	0.00%

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Financing receivable gross carrying amount commercial percentage.

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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=121593590&loc=d3e4428-111522

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