Business Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Fixed income	$ 45,506	$ 50,678
Deposit transactions and cash management	31,162	24,565
Brokerage, management fees and commissions	13,483	11,906
Bankcard income	11,267	5,455
Trust services and investment management	7,277	6,653
Bank-owned life insurance	3,993	3,247
Debt securities gains/(losses), net	52	44
Equity securities gains/(losses), net	34	0
All other income and commissions	23,243	14,391
Total noninterest income	136,017	116,939
Noninterest expense, other	8,200
Gain on sale of a building	3,300
Regional Banking
Disaggregation of Revenue [Line Items]
Fixed income	81	74
Deposit transactions and cash management	29,918	23,234
Brokerage, management fees and commissions	13,483	11,906
Bankcard income	11,115	5,342
Trust services and investment management	7,292	6,680
Bank-owned life insurance	0	0
Debt securities gains/(losses), net	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions	16,964	11,742
Total noninterest income	78,853	58,978
Fixed Income
Disaggregation of Revenue [Line Items]
Fixed income	45,425	50,604
Deposit transactions and cash management	3	0
Brokerage, management fees and commissions	0	0
Bankcard income	0	0
Trust services and investment management	0	0
Bank-owned life insurance	0	0
Debt securities gains/(losses), net	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions	177	219
Total noninterest income	45,605	50,823
Corporate
Disaggregation of Revenue [Line Items]
Fixed income	0	0
Deposit transactions and cash management	1,194	1,289
Brokerage, management fees and commissions	0	0
Bankcard income	57	56
Trust services and investment management	(15)	(27)
Bank-owned life insurance	3,993	3,247
Debt securities gains/(losses), net	52	44
Equity securities gains/(losses), net	34	0
All other income and commissions	4,164	867
Total noninterest income	9,479	5,476
Non-Strategic
Disaggregation of Revenue [Line Items]
Fixed income	0	0
Deposit transactions and cash management	47	42
Brokerage, management fees and commissions	0	0
Bankcard income	95	57
Trust services and investment management	0	0
Bank-owned life insurance	0	0
Debt securities gains/(losses), net	0	0
Equity securities gains/(losses), net	0	0
All other income and commissions	1,938	1,563
Total noninterest income	$ 2,080	$ 1,662

Bankcard Other Income

No definition available.

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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.

+ References

No definition available.

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- Definition

Debt Securities, Realized Gain (Loss)

+ References

No definition available.

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- Definition

Deposit transactions and cash management.

+ References

No definition available.

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- Definition

Equity Securities, FV-NI, Realized Gain (Loss)

+ References

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

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

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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.

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No definition available.

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- Definition

Income from services rendered by trust departments or by any consolidated subsidiaries acting in a fiduciary capacity, including fees earned for (1) acting as an agent for fiduciary placement and loans and (2) custody or investment advisory services when such fees are not separately billed to the customer. This item excludes commissions and fees received for the accumulation or disbursement of funds deposited to Individual Retirement or Keogh plan accounts when such are not handled by the reporting entity's trust department.

+ References

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

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.

+ References

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- Definition

Represents the total of noninterest income derived from certain activities and assets including (for example): (1) venture capital investments; (2) bank owned life insurance; (3) foreign currency transactions; and (4) mortgage servicing rights.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-03(1)(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20187-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(4))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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