Business Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Fixed income	$ 95,635	$ 53,749
Deposit transactions and cash management	30,290	31,621
Brokerage, management fees and commissions	15,405	12,633
Bankcard income	7,253	6,952
Trust services and investment management	7,195	7,026
Bank-owned life insurance (BOLI)	4,589	4,402
Equity securities gains/(losses), net	25	31
All other income and commissions (Note 7)	14,364	24,631
Total noninterest income	174,756	141,045
Regional Banking
Disaggregation of Revenue [Line Items]
Fixed income	121	17
Deposit transactions and cash management	28,812	30,003
Brokerage, management fees and commissions	15,405	12,630
Bankcard income	7,150	7,039
Trust services and investment management	7,213	7,056
Bank-owned life insurance (BOLI)	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions (Note 7)	23,170	16,284
Total noninterest income	81,871	73,029
Fixed Income
Disaggregation of Revenue [Line Items]
Fixed income	95,514	53,732
Deposit transactions and cash management	0	3
Brokerage, management fees and commissions	0	0
Bankcard income	0	0
Trust services and investment management	0	0
Bank-owned life insurance (BOLI)	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions (Note 7)	209	72
Total noninterest income	95,723	53,807
Corporate
Disaggregation of Revenue [Line Items]
Fixed income	0	0
Deposit transactions and cash management	1,435	1,563
Brokerage, management fees and commissions	0	0
Bankcard income	70	62
Trust services and investment management	(18)	(30)
Bank-owned life insurance (BOLI)	4,589	4,402
Equity securities gains/(losses), net	25	31
All other income and commissions (Note 7)	(9,819)	7,325
Total noninterest income	(3,718)	13,353
Non-Strategic
Disaggregation of Revenue [Line Items]
Fixed income	0	0
Deposit transactions and cash management	43	52
Brokerage, management fees and commissions	0	3
Bankcard income	33	(149)
Trust services and investment management	0	0
Bank-owned life insurance (BOLI)	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions (Note 7)	804	950
Total noninterest income	880	856
Underwriting, portfolio advisory, and other noninterest income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 9,300	$ 7,300

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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- Definition

Deposit transactions and cash management.

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No definition available.

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- Definition

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.

+ References

No definition available.

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- Definition

Trust Services And Investment Management

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No definition available.

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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
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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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No definition available.

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- Definition

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).

+ References

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 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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- Definition

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
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-Publisher FASB
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