Borrowed Funds (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Short-term borrowings
Total short-term borrowings	$ 4,635	$ 3,889
Long-term debt
Long-term debt	631,434	735,968
5.25% Senior Notes Due September 2020 | City National Corporation
Long-term debt
Long-term debt	299,521	299,463
Fixed interest rate (as a percent)	5.25%	5.25%
9.00% Subordinated Notes Due July 2019 | City National Bank
Long-term debt
Long-term debt		50,000
Fixed interest rate (as a percent)		9.00%
Interest rate for initial period (as a percent)	9.00%
Initial interest rate period	5 years
9.00% Subordinated Notes Due August 2019 | City National Bank
Long-term debt
Long-term debt	75,000	75,000
Fixed interest rate (as a percent)	9.00%	9.00%
Fixed and Floating Subordinated Notes due August 2019 | City National Bank
Long-term debt
Long-term debt		55,000
Interest rate for initial period (as a percent)	9.00%
Initial interest rate period	5 years
5.375% Subordinated Notes Due July 2022 | City National Bank
Long-term debt
Long-term debt	149,994	149,994
Fixed interest rate (as a percent)	5.375%	5.375%
Floating Rate Securities Due November 2034 | Business Bancorp Capital Trust I
Long-term debt
Long-term debt	5,155	5,155
Variable rate basis	three-month LIBOR
Basis spread (as a percent)	1.965%
Interest rate as of reporting date (as a percent)	2.20%
Nonrecourse debt
Short-term borrowings
Current portion of subordinated debt	4,635	3,889
Long-term debt
Long-term debt	91,941	91,388
Average interest rate (as a percent)	3.85%
Other long-term debt
Long-term debt
Long-term debt	$ 9,823	$ 9,968
Fixed interest rate (as a percent)	5.64%