Branch sale of deposits.

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- Definition

Business combination cash consideration, per share amount.

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No definition available.

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- Definition

Business combination equity interest exchange ratio.

+ References

No definition available.

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- Definition

Net gain realized from the divestitures of certain branch offices, which may include deposit and loan premiums, goodwill allocations, and certain other fees associated with the transactions.

+ References

No definition available.

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- Definition

Number of banking centers consolidated into existing branch locations.

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No definition available.

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- Definition

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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Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

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Number of shares of equity interests issued or issuable to acquire entity.

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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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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of assets acquired at the acquisition date.

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Amount of liabilities assumed at the acquisition date.

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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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

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Represents the number of stores.

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No definition available.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Price of a single share of a number of saleable stocks of a company.

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No definition available.

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Acquisition and Divestiture Activity - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($) Branch $ / shares shares	Dec. 31, 2017 Branch	Sep. 28, 2018 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Jun. 20, 2018 Branch	Nov. 01, 2017 Branch
Business Acquisition [Line Items]
Value of issuance common stock shares				$ 439.5
Number of banking centers consolidated \| Branch		10	29
Closing price per share \| $ / shares				$ 19.30
Marine Credit Union of La Crosse, Wisconsin [member]
Business Acquisition [Line Items]
Number of branches \| Branch		10
Branch sale of deposits		$ 231.0
Scenario, Forecast [Member] \| Marine Credit Union of La Crosse, Wisconsin [member]
Business Acquisition [Line Items]
Net gain on branch divestitures	$ 14.0
Anchor Bank (MN) [Member]
Business Acquisition [Line Items]
Consideration received in cash by merged entity \| $ / shares		$ 2.625
Portion of share received by merged entity		1.350
Total fair value of consideration paid		$ 332.8
Purchase price of acquisition, cash		$ 31.9
Issuance of common stock shares for acquisitions of business \| shares		16.5
Value of issuance common stock shares		$ 300.8
Transaction and integration costs associated with the acquisition		18.1
Anchor Bank (MN) [Member] \| Core Deposit [Member]
Business Acquisition [Line Items]
Estimated fair value of intangible assets acquired		$ 26.6
Estimated useful life of intangible assets		10 years
Anchor Bank (MN) [Member] \| Minnesota [Member]
Business Acquisition [Line Items]
Number of branches \| Branch							17
Minnesota-based Klein [Member]
Business Acquisition [Line Items]
Number of branches \| Branch						18
Portion of share received by merged entity						7.92
Stock merger acquisition ratio						100.00%
Reported total assets of acquire					$ 2,000.0
Total deposit liabilities held by acquire					$ 1,700.0