Core Deposit Intangibles - Schedule of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 102,396	$ 85,869
Accumulated amortization	(68,948)	(67,434)
Total core deposit intangibles	33,448	34,962
Core deposit intangibles acquired
Finite-Lived Intangible Assets [Line Items]
Core deposit intangibles acquired		$ 16,527

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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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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