Parent Company Only Condensed Financial Statements (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income
Gain (loss) on sale of securities	$ 1,113	$ 5,066	$ 393
Expenses
Income (loss) before taxes and equity in undistributed income of Bank and non-bank subsidiaries	307,955	253,616	161,152
Income tax benefit	98,822	77,561	26,055
Net income	209,133	176,055	135,097
Less: Net loss attributable to noncontrolling interest	1,084	3,634	3,920
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
Parent Company
Income
Dividends from Bank and non-bank subsidiaries	89,000	30,000
Interest and dividend income and other income	20,308	14,171	6,209
Gain (loss) on sale of securities	930	3,170	(509)
Total income	110,238	47,341	5,700
Expenses
Interest on other borrowings	18,779	18,533	26,567
Other expenses	10,631	5,804	4,097
Total expenses	29,410	24,337	30,664
Income (loss) before taxes and equity in undistributed income of Bank and non-bank subsidiaries	80,828	23,004	(24,964)
Income tax benefit	(3,424)	(8,059)	(15,942)
Income (loss) before equity in undistributed income of Bank and non-bank subsidiaries	84,252	31,063	(9,022)
Equity in undistributed income of Bank and non-bank subsidiaries	123,797	141,358	139,486
Net income	208,049	172,421	130,464
Less: Net loss attributable to noncontrolling interest			(713)
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