Business Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Fixed income	$ 278,789	$ 167,882	$ 216,625
Deposit transactions and cash management	131,663	133,281	110,592
Brokerage, management fees and commissions	55,467	54,803	48,514
Trust services and investment management	29,511	29,806	28,420
Bankcard income	28,308	29,304	26,435
Bank-owned life insurance (BOLI)	19,210	18,955	15,124
Debt securities gains/(losses), net	(267)	52	483
Equity securities gains/(losses), net	441	212,896	109
Other income/(loss)	110,958	75,809	43,917
Total noninterest income	654,080	722,788	490,219
Gain on sale of TRUPs loans	1,105	3,777	0
Visa Class B Shares
Disaggregation of Revenue [Line Items]
Gain on sale of investments		212,900
Underwriting, Portfolio Advisory, and Other Noninterest Income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	33,700	28,900
Regional Banking
Disaggregation of Revenue [Line Items]
Fixed income	122	417	430
Deposit transactions and cash management	124,832	126,832	105,058
Brokerage, management fees and commissions	55,462	54,800	48,513
Trust services and investment management	29,600	29,852	28,491
Bankcard income	28,540	29,434	25,983
Bank-owned life insurance (BOLI)	0	0	0
Debt securities gains/(losses), net	0	0	386
Equity securities gains/(losses), net	0	0	0
Other income/(loss)	91,278	70,428	50,685
Total noninterest income	329,834	311,763	259,546
Fixed Income
Disaggregation of Revenue [Line Items]
Fixed income	277,561	163,382	216,195
Deposit transactions and cash management	4	12	3
Brokerage, management fees and commissions	0	0	0
Trust services and investment management	0	0	0
Bankcard income	11	0	0
Bank-owned life insurance (BOLI)	0	0	0
Debt securities gains/(losses), net	0	0	0
Equity securities gains/(losses), net	0	0	0
Other income/(loss)	847	1,375	888
Total noninterest income	278,423	164,769	217,086
Corporate
Disaggregation of Revenue [Line Items]
Fixed income	0	0	0
Deposit transactions and cash management	6,610	6,214	5,338
Brokerage, management fees and commissions	0	0	1
Trust services and investment management	(89)	(46)	(71)
Bankcard income	248	226	225
Bank-owned life insurance (BOLI)	19,210	18,955	15,124
Debt securities gains/(losses), net	(267)	52	97
Equity securities gains/(losses), net	441	212,896	109
Other income/(loss)	15,204	966	(11,936)
Total noninterest income	41,357	239,263	8,887
(Gain)/loss on securities			14,300
Non-Strategic
Disaggregation of Revenue [Line Items]
Fixed income	1,106	4,083	0
Deposit transactions and cash management	217	223	193
Brokerage, management fees and commissions	5	3	0
Trust services and investment management	0	0	0
Bankcard income	(491)	(356)	227
Bank-owned life insurance (BOLI)	0	0	0
Debt securities gains/(losses), net	0	0	0
Equity securities gains/(losses), net	0	0	0
Other income/(loss)	3,629	3,040	4,280
Total noninterest income	4,466	6,993	$ 4,700
Gain on sale of TRUPs loans	$ 1,100	$ 4,100

Bankcard Other Income

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- Definition

Acting as an agent, a broker-dealer may buy and sell securities on behalf of its customers. In return for such services, the broker-dealer charges a commission. Each time a customer enters into a buy or sell transaction, a commission is earned by the broker-dealer for its selling and administrative efforts. For securities purchased, the commission is recorded as a receivable from customers; for securities sold, it is recorded as reductions in the payable to customers. Commissions earned are usually related to the broker-dealer's customers' trading volume and the dollar amounts of the trades. In general, commissions are for smaller trades of exchange-listed stocks and bonds made by retail customers. Revenue recognized in the period for (1) performance (incentive) fees based on the investment results achieved for management of certain institutional accounts and hedge funds, (2) schedule-based fees earned for management of mutual funds and closed-end funds, based either on average daily net assets or on a combination of the average daily net assets and gross income, and (3) other investment management and advisory fees.

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Deposit transactions and cash management.

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The major component of revenue in this line item is generated from the purchase and sale of securities as both principal and agent, and from other fee sources including loan sales, portfolio advisory, and derivative sales.

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No definition available.

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Gain On Sale Of Held To Maturity Loans

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Trust Services And Investment Management

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- Definition

Earnings on or other increases in the value of the cash surrender value of bank owned life insurance policies.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13)
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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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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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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

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No definition available.

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The difference between the carrying value and the sale price of an investment. A gain would be recognized when the sale price of the investment is greater than the carrying value of the investment. This element refers to the Gain included in earnings and not to the cash proceeds of the sale.

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The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

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Amount of revenue earned, classified as other, excluding interest income.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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