Segment Results (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 segment	Dec. 31, 2010	Dec. 31, 2009
Segment Results
Number of reportable segments	3
Earnings Summary:
Net interest income	$ 772,990	$ 730,325	$ 624,053
Provision for credit losses on loans and leases, excluding covered loans	12,500	103,000	285,000
Provision for losses on covered loans	43,646	76,218
Noninterest income	341,867	361,375	292,197
Depreciation and amortization	35,323	34,881	33,576
Noninterest expense	769,772	716,449	547,511
Income (loss) before income taxes	253,616	161,152	50,163
Provision (benefit) for income taxes	77,561	26,055	(1,886)
Net income	176,055	135,097	52,049
Less: Net income attributable to noncontrolling interest	3,634	3,920	710
Net income attributable to City National Corporation	172,421	131,177	51,339
Selected Average Balances:
Loans and leases, excluding covered loans	11,698,388	11,576,380	12,296,619
Covered loans	1,699,182	1,940,316	66,470
Total assets	22,527,750	21,156,661	17,711,495
Deposits	19,305,703	17,868,392	14,351,898
Goodwill	486,502	481,018	469,446
Customer-relationship intangibles, net	39,428	43,171	40,784
Commercial and Private Banking
Earnings Summary:
Net interest income	740,445	702,794	623,033
Provision for credit losses on loans and leases, excluding covered loans	12,500	103,000	285,000
Provision for losses on covered loans	43,646	76,218
Noninterest income	222,279	277,883	203,896
Depreciation and amortization	14,656	13,764	12,717
Noninterest expense	683,962	629,692	464,578
Income (loss) before income taxes	207,960	158,003	64,634
Provision (benefit) for income taxes	87,344	66,361	27,146
Net income	120,616	91,642	37,488
Net income attributable to City National Corporation	120,616	91,642	37,488
Selected Average Balances:
Loans and leases, excluding covered loans	11,641,976	11,530,140	12,258,766
Covered loans	1,699,182	1,940,316	66,470
Total assets	13,820,611	14,134,625	12,502,890
Deposits	18,862,701	17,289,288	13,224,009
Goodwill	324,872	319,376	317,802
Customer-relationship intangibles, net	11,713	12,563	9,550
Wealth Management
Earnings Summary:
Net interest income	2,113	1,694	2,357
Noninterest income	162,238	155,724	145,582
Depreciation and amortization	5,205	6,507	6,050
Noninterest expense	147,161	145,175	137,309
Income (loss) before income taxes	11,985	5,736	4,580
Provision (benefit) for income taxes	4,212	1,662	2,535
Net income	7,773	4,074	2,045
Less: Net income attributable to noncontrolling interest	1,956	1,779	(1,457)
Net income attributable to City National Corporation	5,817	2,295	3,502
Selected Average Balances:
Loans and leases, excluding covered loans		50
Total assets	549,917	557,818	575,546
Deposits	64,919	47,450	62,726
Goodwill	161,630	161,642	151,644
Customer-relationship intangibles, net	27,715	30,608	31,234
Other
Earnings Summary:
Net interest income	30,432	25,837	(1,337)
Noninterest income	(42,650)	(72,232)	(57,281)
Depreciation and amortization	15,462	14,610	14,809
Noninterest expense	(61,351)	(58,418)	(54,376)
Income (loss) before income taxes	33,671	(2,587)	(19,051)
Provision (benefit) for income taxes	(13,995)	(41,968)	(31,567)
Net income	47,666	39,381	12,516
Less: Net income attributable to noncontrolling interest	1,678	2,141	2,167
Net income attributable to City National Corporation	45,988	37,240	10,349
Selected Average Balances:
Loans and leases, excluding covered loans	56,412	46,190	37,853
Total assets	8,157,222	6,464,218	4,633,059
Deposits	$ 378,083	$ 531,654	$ 1,065,163