Earnings per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Basic EPS:
Net income attributable to City National Corporation	$ 208,049	$ 172,421	$ 131,177
Less: Dividends and accretion on preferred stock			5,702
Net income available to common shareholders	208,049	172,421	125,475
Less: Earnings allocated to participating securities	3,008	2,678	1,605
Earnings allocated to common shareholders	205,041	169,743	123,870
Weighted average common shares outstanding	53,211,000	52,439,000	51,992,000
Basic earnings per common share (in dollars per share)	$ 3.85	$ 3.24	$ 2.38
Diluted EPS:
Earnings allocated to common shareholders	$ 205,050	$ 169,759	$ 123,882
Weighted average common shares outstanding	53,211,000	52,439,000	51,992,000
Dilutive effect of equity awards (in shares)	264,000	410,000	463,000
Weighted average diluted common shares outstanding	53,475,000	52,849,000	52,455,000
Diluted earnings per common share (in dollars per share)	$ 3.83	$ 3.21	$ 2.36
Average outstanding stock options
Antidilutive securities not included in calculation of diluted EPS:
Antidilutive securities not included in calculation of diluted EPS (in shares)	2,800,000	2,900,000	1,900,000
Average outstanding common stock warrant
Antidilutive securities not included in calculation of diluted EPS:
Antidilutive securities not included in calculation of diluted EPS (in shares)			300,000