Business Combination, Acquired Receivables, Increase Decrease

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Shares transferred at acquisition-date in consideration of business combination.

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- Definition

Estimate Acquired Deposits

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Estimate Acquired Loans

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Estimate Acquired Net Branches

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Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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- Definition

Number of shares of stock issued during the period pursuant to acquisitions.

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Acquisition Narrative (Details)		3 Months Ended			12 Months Ended
Acquisition Narrative (Details)	Feb. 01, 2018 USD ($) shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 11, 2018 USD ($) branch
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable					$ 488,408,000	$ 7,151,000	$ 0
Bank Mutual [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 482,000,000
Consideration shares transferred \| shares	0.422
Stock Issued During Period, Shares, Acquisitions \| shares	19,500,000
Goodwill acquired during period	$ 175,000,000
Additions to finite-lived intangible assets	$ 58,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
BKMU Goodwill Acquired Adjustments [Member]
Business Acquisition [Line Items]
Goodwill acquired during period		$ 2,000,000	$ 6,000,000
BKMU Assets Acquired Liabilities Assumed IncreaseDecrease [Member]
Business Acquisition [Line Items]
Premises and equipment, net		$ 2,000,000	6,000,000
Business Combination, Acquired Receivables, IncreaseDecrease	less than $1 million
Anderson Insurance Investment Agency [Domain]
Business Acquisition [Line Items]
Goodwill acquired during period			7,000,000
Business Combination, Consideration Transferred			10,000,000
Additions to finite-lived intangible assets			$ 3,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			7 years
Diversified Insurance [Member]
Business Acquisition [Line Items]
Goodwill acquired during period				$ 10,000,000
Business Combination, Consideration Transferred				19,000,000
Additions to finite-lived intangible assets				$ 8,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				10 years
Huntington National Bank [Domain]
Business Acquisition [Line Items]
Estimate Acquired Deposits								$ 850,000,000
Estimate Acquired Loans								$ 134,000,000
Estimate Acquired Net Branches \| branch								14