Junior Subordinated Debentures - Summary of Trust Preferred Securities and Related Common Securities of Trust (Parenthetical) (Detail) (Junior subordinated debt [Member])	12 Months Ended
	Dec. 31, 2013
Bank of commerce holdings trust [Member]
Subordinated Borrowing [Line Items]
Reference rate for variable rate adjusted quarterly	Rate based on three month London Interbank Offered Rate (LIBOR) plus 3.30% adjusted quarterly.
Rate based on three month LIBOR plus adjusted quarterly	3.30%
Rate increase capped	2.75%
Lifetime cap	12.50%
Bank of commerce holdings trust II [Member]
Subordinated Borrowing [Line Items]
Reference rate for variable rate adjusted quarterly	Rate based on three month LIBOR plus 1.58% adjusted quarterly
Rate based on three month LIBOR plus adjusted quarterly	1.58%