Fair Value Measurements Details of Book Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Available for sale investment securities	$ 2,497,537	$ 2,080,294
Held to maturity investment securities	383,705
FHLB advances and long-term debt	881,769	992,279
Book Value
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	517,791	445,687
FRB and FHLB stock	97,422	79,283
Loans held for sale	37,828	27,099
Available for sale investment securities	2,497,537	2,080,294
Held to maturity investment securities	369,841	606,679
Net loans and leases	16,673,904	16,005,263
Accrued interest receivable	60,898	58,879
Total assets	431,565	235,782
Demand and savings deposits	14,327,453	13,478,016
Brokered deposits	264,531	176,239
Time deposits	2,801,930	2,721,904
Short-term borrowings	883,241	754,777
Accrued interest payable	8,834	10,529
FHLB advances and long-term debt	881,769	992,279
Other liabilities	221,542	218,061
Estimated Fair Value
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	517,791	445,687
FRB and FHLB stock	97,422	79,283
Loans held for sale	37,828	27,099
Available for sale investment securities	2,497,537	2,080,294
Held to maturity investment securities	383,705	611,419
Net loans and leases	16,485,122	15,446,895
Accrued interest receivable	60,898	58,879
Total assets	431,565	235,782
Demand and savings deposits	14,327,453	13,478,016
Brokered deposits	264,531	176,239
Time deposits	2,828,988	2,712,296
Short-term borrowings	883,241	754,777
Accrued interest payable	8,834	10,529
FHLB advances and long-term debt	878,385	970,985
Other liabilities	221,542	218,061
Level 1 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	517,791	445,687
FRB and FHLB stock	0	0
Loans held for sale	0	0
Available for sale investment securities	0	0
Held to maturity investment securities	0	611,419
Net loans and leases	0	0
Accrued interest receivable	60,898	58,879
Total assets	234,176	124,138
Demand and savings deposits	14,327,453	13,478,016
Brokered deposits	223,982	176,239
Time deposits	0	0
Short-term borrowings	883,241	754,777
Accrued interest payable	8,834	10,529
FHLB advances and long-term debt	0	0
Other liabilities	142,508	161,003
Level 2 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	0	0
FRB and FHLB stock	97,422	79,283
Loans held for sale	37,828	27,099
Available for sale investment securities	2,393,211	1,974,025
Held to maturity investment securities	383,705	0
Net loans and leases	0	0
Accrued interest receivable	0	0
Total assets	145,365	62,552
Demand and savings deposits	0	0
Brokered deposits	40,549	0
Time deposits	2,828,988	2,712,296
Short-term borrowings	0	0
Accrued interest payable	0	0
FHLB advances and long-term debt	878,385	970,985
Other liabilities	76,447	48,185
Level 3 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	0	0
FRB and FHLB stock	0	0
Loans held for sale	0	0
Available for sale investment securities	104,326	106,269
Held to maturity investment securities	0	0
Net loans and leases	16,485,122	15,446,895
Accrued interest receivable	0	0
Total assets	52,024	49,092
Demand and savings deposits	0	0
Brokered deposits	0	0
Time deposits	0	0
Short-term borrowings	0	0
Accrued interest payable	0	0
FHLB advances and long-term debt	0	0
Other liabilities	$ 2,587	$ 8,873

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Demand and Savings Deposit Liabilities, Fair Value Disclosure

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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer. Also including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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Interest Receivable, Fair Value Disclosure

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Loans, Net Of Deferred Income, Fair Value Disclosure

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Other financial liabilities – Included within this category are: Level 1 employee deferred compensation liabilities which represent amounts due to employees under the deferred compensation plans, described under the heading “Other financial assets” above and Level 2 mortgage banking derivatives, described under the heading “Other financial assets” above.

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Time Deposit Liabilities, Fair Value Disclosure

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Fair value portion of trade and related party payables and accrued expenses.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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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.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 5
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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of other assets.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

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