Earnings per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic EPS:
Net income attributable to City National Corporation	$ 68,651	$ 63,633	$ 189,863	$ 174,897
Less: Dividends on preferred stock	4,093	2,407	12,281	7,219
Net income available to common shareholders	64,558	61,226	177,582	167,678
Less: Earnings allocated to participating securities	632	688	1,808	1,975
Earnings allocated to common shareholders	63,926	60,538	175,774	165,703
Weighted average common shares outstanding	55,031,000	54,274,000	54,893,000	54,039,000
Basic earnings per common share (in dollars per share)	$ 1.16	$ 1.12	$ 3.20	$ 3.07
Diluted EPS:
Earnings allocated to common shareholders	$ 63,932	$ 60,543	$ 175,790	$ 165,716
Weighted average common shares outstanding	55,031,000	54,274,000	54,893,000	54,039,000
Dilutive effect of equity awards (in shares)	734,000	546,000	723,000	425,000
Weighted average diluted common shares outstanding	55,765,000	54,820,000	55,616,000	54,464,000
Diluted earnings per common share (in dollars per share)	$ 1.15	$ 1.10	$ 3.16	$ 3.04
Average outstanding stock options
Antidilutive securities not included in calculation of diluted EPS:
Antidilutive securities not included in calculation of diluted EPS (in shares)	700,000	1,000,000	700,000	1,900,000