The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Bank deposits belonging to an acquired bank that can be counted on as a stable source of lending funds. These deposits have the following attributes: predictable costs and low sensitivity to interest rates. This intangible asset is usually amortized over its estimated useful life.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Amount of expense charged against earnings to allocate the cost of tangible and intangible assets over their remaining economic lives, classified as other.

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GOODWILL AND OTHER INTANGIBLE ASSETS--Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 01, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill resulting from business combinations	$ 675,643			$ (524)	$ 678,941	$ 676,167
Goodwill		$ 879,727		879,727		880,251	$ 204,084
Intangible Assets, Net (Excluding Goodwill)		36,300		36,300		40,800
Finite-Lived Core Deposits, Gross		33,800		33,800		$ 37,900
Other Depreciation and Amortization		2,000		4,100	2,600
Amortization of Intangible Assets		$ 2,044	$ 2,364	$ 4,089	$ 2,644
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization method				accelerated basis
Estimated weighted average life (in years)				8 years 4 months 24 days