Borrowings - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2009	Dec. 31, 2009	Dec. 31, 2006	Dec. 15, 2013	Jan. 31, 2006
Debt Instrument [Line Items]
Funds borrowed under repurchase agreement	$ 563,600,000	$ 643,300,000
Weighted average interest rates	0.24%	0.29%
FHLB advance	199,500,000	199,200,000
Weighted average interest rate	4.52%	4.52%
FHLB advance maturity date	Nov. 28, 2016
Average outstanding balance	199,400,000	199,100,000
Maximum outstanding balance	199,500,000	199,200,000
Loans at carrying value	2,780,000,000
Investment securities at carrying value	3,110,000,000
Prepayment penalties on borrowings	0	0	20,400,000
Overnight borrowings	46,000,000	69,000,000
Overnight borrowings with cost basis points	0.10%	0.06%
CVB Statutory Trust II [Member] | Junior Subordinated Debenture Held by CVB Statutory Trust II [Member]
Debt Instrument [Line Items]
Trust preferred securities, offered fair value							40,000,000
Proceeds from the offering and other cash							41,238,000
Maximum Period of Deferred payments of interest	20 consecutive quarters
Trust Preferred Securities, maturity date	Jan. 07, 2034
Trust Preferred Securities, fixed interest rate during first five years	6.46%
Trust Preferred Securities, interest rate in excess of LIBOR					2.85%
Period of LIBOR				3 months
Trust Preferred Securities callable date	Jan. 07, 2009
CVB Statutory Trust III [Member] | Junior Subordinated Debenture Held by CVB Statutory Trust III [Member]
Debt Instrument [Line Items]
Trust preferred securities, offered fair value								25,000,000
Proceeds from the offering and other cash								$ 25,774,000
Maximum Period of Deferred payments of interest	20 consecutive quarters
Trust Preferred Securities, maturity date	Mar. 15, 2036
Trust Preferred Securities, interest rate in excess of LIBOR						1.38%
Period of LIBOR				1 year
Trust Preferred Securities callable date	Mar. 15, 2011