Business Combinaions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Detail) - USD ($) shares in Thousands, $ in Thousands	Aug. 10, 2018	Sep. 30, 2018	Dec. 31, 2017
Liabilities assumed
Goodwill		$ 662,888	$ 116,564
Community Bank [Member]
Merger Consideration
Cash paid	$ 180,719
CVBF common stock issued	722,767
Total merger consideration	$ 903,486
Identifiable net assets acquired, at fair value
Cash and cash equivalents	47,802
Investment securities	716,996
FHLB stock	17,250
Loans	2,734,081
Accrued interest receivable	7,916
Premises and equipment	14,632
BOLI	70,904
Core deposit intangible	52,200
Other assets	58,130
Total assets acquired	3,719,911
Liabilities assumed
Deposits	2,869,986
FHLB advances	297,571
Other borrowings	166,000
Other liabilities	29,192
Total liabilities assumed	3,362,749
Total fair value of identifiable net assets, at fair value	357,162
Goodwill	$ 546,324