Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue
Net interest income (1)	$ 139,672	$ 129,345
Not in scope of Topic 606 (1)	3,424
Noninterest Income	48,700	51,059
Total revenue	188,372
Retail Banking
Disaggregation of Revenue
Net interest income (1)	109,654	105,701
Not in scope of Topic 606 (1)	2,160
Noninterest Income	22,732	23,619
Total revenue	132,386
Commercial Banking
Disaggregation of Revenue
Net interest income (1)	27,879	27,533
Not in scope of Topic 606 (1)	(1,330)
Noninterest Income	20,000	18,834
Total revenue	47,879
Treasury and Other
Disaggregation of Revenue
Net interest income (1)	2,139	(3,889)
Not in scope of Topic 606 (1)	2,594
Noninterest Income	5,968	$ 8,606
Total revenue	8,107
Service charges on deposit accounts
Disaggregation of Revenue
Revenue by type of service	7,955
Service charges on deposit accounts \| Retail Banking
Disaggregation of Revenue
Revenue by type of service	7,448
Service charges on deposit accounts \| Commercial Banking
Disaggregation of Revenue
Revenue by type of service	4
Service charges on deposit accounts \| Treasury and Other
Disaggregation of Revenue
Revenue by type of service	503
Credit and debit card fees
Disaggregation of Revenue
Revenue by type of service	20,408
Credit and debit card fees \| Commercial Banking
Disaggregation of Revenue
Revenue by type of service	18,621
Credit and debit card fees \| Treasury and Other
Disaggregation of Revenue
Revenue by type of service	1,787
Other service charges and fees
Disaggregation of Revenue
Revenue by type of service	6,276
Other service charges and fees \| Retail Banking
Disaggregation of Revenue
Revenue by type of service	4,745
Other service charges and fees \| Commercial Banking
Disaggregation of Revenue
Revenue by type of service	898
Other service charges and fees \| Treasury and Other
Disaggregation of Revenue
Revenue by type of service	633
Trust and investment services income
Disaggregation of Revenue
Revenue by type of service	8,231
Trust and investment services income \| Retail Banking
Disaggregation of Revenue
Revenue by type of service	8,231
Other
Disaggregation of Revenue
Revenue by type of service	2,406
Other \| Retail Banking
Disaggregation of Revenue
Revenue by type of service	148
Other \| Commercial Banking
Disaggregation of Revenue
Revenue by type of service	1,807
Other \| Treasury and Other
Disaggregation of Revenue
Revenue by type of service	$ 451

Noninterest income (expense) amounts that are not in scope of Topic 606.

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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

The net amount of operating interest income (expense).

+ 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 210.9-04.10)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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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.

+ 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

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
-Paragraph 2A
-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL82860478-203043

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130539-203045

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130545-203045

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
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