Segment Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 item	Sep. 30, 2013
Segment Results
Number of reportable segments			3
Earnings Summary:
Net interest income	$ 215,776	$ 214,271	$ 634,676	$ 618,263
(Reversal of) provision for credit losses on loans and leases, excluding covered loans	(8,000)		(9,000)
Provision for losses on covered loans	589	2,496	3,783	461
Noninterest income	107,917	88,883	310,264	264,620
Depreciation and amortization	9,702	9,759	28,356	30,043
Noninterest expense	217,500	199,605	639,361	602,090
Income before income taxes	103,902	91,294	282,440	250,289
Provision for income taxes	34,404	27,052	90,521	73,735
Net income	69,498	64,242	191,919	176,554
Less: Net income attributable to noncontrolling interest	847	609	2,056	1,657
Net income attributable to City National Corporation	68,651	63,633	189,863	174,897
Selected Average Balances:
Loans and leases, excluding covered loans	18,837,760	16,039,753	18,050,616	15,432,239
Covered loans	580,200	818,928	639,592	905,411
Total assets	30,910,614	28,061,134	30,110,744	27,747,914
Deposits	26,830,633	24,301,647	26,043,449	23,284,065
Goodwill	642,255	642,622	642,498	642,622
Customer-relationship intangibles, net	37,024	43,469	38,505	45,371
Other segment
Earnings Summary:
Net interest income	10,359	18,917	30,253	53,328
Noninterest income	(15,448)	(7,254)	(35,810)	(26,259)
Depreciation and amortization	5,119	4,618	14,665	13,884
Noninterest expense	(21,858)	(18,598)	(61,939)	(54,093)
Income before income taxes	11,650	25,643	41,717	67,278
Provision for income taxes	3,889	7,650	13,468	19,952
Net income	7,761	17,993	28,249	47,326
Net income attributable to City National Corporation	7,761	17,993	28,249	47,326
Selected Average Balances:
Loans and leases, excluding covered loans	60,002	50,572	57,583	53,303
Total assets	10,689,909	10,404,910	10,600,175	10,597,656
Deposits	277,930	408,512	254,929	487,093
Commercial and Private Banking
Earnings Summary:
Net interest income	204,965	195,112	603,170	564,132
(Reversal of) provision for credit losses on loans and leases, excluding covered loans	(8,000)		(9,000)
Provision for losses on covered loans	589	2,496	3,783	461
Noninterest income	53,391	38,602	142,536	119,418
Depreciation and amortization	2,786	3,263	8,381	10,505
Noninterest expense	181,632	169,862	533,442	511,703
Income before income taxes	81,349	58,093	209,100	160,881
Provision for income taxes	27,158	17,329	67,507	47,712
Net income	54,191	40,764	141,593	113,169
Net income attributable to City National Corporation	54,191	40,764	141,593	113,169
Selected Average Balances:
Loans and leases, excluding covered loans	18,777,758	15,989,181	17,993,033	15,378,936
Covered loans	580,200	818,928	639,592	905,411
Total assets	19,482,692	17,011,547	18,814,042	16,502,985
Deposits	26,481,108	23,817,083	25,710,863	22,696,050
Goodwill	393,176	393,176	393,176	393,176
Customer-relationship intangibles, net	2,335	4,445	2,717	5,174
Wealth Management
Earnings Summary:
Net interest income	452	242	1,253	803
Noninterest income	69,974	57,535	203,538	171,461
Depreciation and amortization	1,797	1,878	5,310	5,654
Noninterest expense	57,726	48,341	167,858	144,480
Income before income taxes	10,903	7,558	31,623	22,130
Provision for income taxes	3,357	2,073	9,546	6,071
Net income	7,546	5,485	22,077	16,059
Less: Net income attributable to noncontrolling interest	847	609	2,056	1,657
Net income attributable to City National Corporation	6,699	4,876	20,021	14,402
Selected Average Balances:
Total assets	738,013	644,677	696,527	647,273
Deposits	71,595	76,052	77,657	100,922
Goodwill	249,079	249,446	249,322	249,446
Customer-relationship intangibles, net	$ 34,689	$ 39,024	$ 35,788	$ 40,197