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The amount of identifiable intangible assets recognized as of the acquisition date.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill, Core Deposit Premium and Other Intangible Assets (Goodwill) (Narrative) (Details) - USD ($)		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Jul. 07, 2017	Feb. 28, 2017	Dec. 31, 2016	Feb. 05, 2016
Goodwill [Line Items]
Goodwill	$ 236,615,000	$ 236,615,000			$ 127,699,000
Goodwill impairment	$ 0
Core Deposits
Goodwill [Line Items]
Intangibles, amortization period		10 years
Citywide Banks
Goodwill [Line Items]
Goodwill			$ 95,154,000
Citywide Banks \| Core Deposits
Goodwill [Line Items]
Intangibles recognized			$ 16,000,000
Founders Bancorp
Goodwill [Line Items]
Goodwill				$ 13,800,000
Founders Bancorp \| Core Deposits
Goodwill [Line Items]
Intangibles recognized				$ 2,500,000
CIC Bancshares, Inc.
Goodwill [Line Items]
Goodwill						$ 29,800,000
CIC Bancshares, Inc. \| Core Deposits
Goodwill [Line Items]
Intangibles recognized						6,400,000
CIC Bancshares, Inc. \| Commercial Servicing Rights
Goodwill [Line Items]
Intangibles recognized						$ 190,000