Loans - Narrative, PCI Loans (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable held-for-sale, amount	$ 0	$ 0
PCI loans	$ 3,509,137,000	$ 3,437,085,000
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of PCI loans	30.00%	29.00%
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of PCI loans	41.00%	42.00%
Purchased Credit-Impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans	$ 16,886,000	$ 17,365,000

Percentage of Purchase Credit Impaired Loans.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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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

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- Definition

The face amount of loans that will be sold to other entities.

+ References

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