Parent Company Only Condensed Financial Statements (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income
Impairment loss on securities	$ (651)	$ (2,031)	$ (16,445)
Gain (loss) on sale of securities	5,066	393	14,286
Expenses
Income (loss) before taxes and equity in undistributed income of Bank and non-bank subsidiaries	253,616	161,152	50,163
Income tax benefit	77,561	26,055	(1,886)
Net income	176,055	135,097	52,049
Less: Net loss attributable to noncontrolling interest	3,634	3,920	710
Net income attributable to City National Corporation	172,421	131,177	51,339
Less: Dividends and accretion on preferred stock		5,702	25,903
Net income available to common shareholders	172,421	125,475	25,436
Parent Company
Income
Dividends from Bank and non-bank subsidiaries	30,000		20,016
Interest and dividend income and other income	14,171	6,209	8,121
Impairment loss on securities			(10,912)
Gain (loss) on sale of securities	3,170	(509)	(7,632)
Total income	47,341	5,700	9,593
Expenses
Interest on other borrowings	18,533	26,567	5,551
Other expenses	5,804	4,097	6,653
Total expenses	24,337	30,664	12,204
Income (loss) before taxes and equity in undistributed income of Bank and non-bank subsidiaries	23,004	(24,964)	(2,611)
Income tax benefit	(8,059)	(15,942)	(16,630)
Income (loss) before equity in undistributed income of Bank and non-bank subsidiaries	31,063	(9,022)	14,019
Equity in undistributed income of Bank and non-bank subsidiaries	141,358	139,486	36,066
Net income	172,421	130,464	50,085
Less: Net loss attributable to noncontrolling interest		(713)	(1,254)
Net income attributable to City National Corporation	172,421	131,177	51,339
Less: Dividends and accretion on preferred stock		5,702	25,903
Net income available to common shareholders	$ 172,421	$ 125,475	$ 25,436