Regulatory Requirements And Capital Ratios (Schedule Of Capital Amounts And Ratios) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Parent Company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital	$ 492,526	$ 430,154
CET1 ratio	15.10%	15.10%
CET1 capital, minimum capital required basel III phase in schedule	$ 208,294	$ 163,441
CET1 ratio, minimum capital required basel III phase in schedule	6.375%	5.75%
CET1 capital, minimum capital required basel III fully phased in	$ 228,715	$ 198,972
CET1 ratio, minimum capital required basel III fully phased in	7.00%	7.00%
CET1 capital, required to be well-capitalized	$ 212,378	$ 184,760
CET1 ratio, required to be well capitalized	6.50%	6.50%
Tier I capital	$ 496,526	$ 446,154
Tier I capital, ratio	15.20%	15.70%
Tier 1, capital, minimum capital required basel III phase in schedule	$ 257,304	$ 206,078
Tier 1, ratio, minimum capital required basel III phase in schedule	7.88%	7.25%
Tier 1, capital, minimum capital required basel III fully phased in	$ 277,725	$ 241,609
Tier 1, ratio, minimum capital required basel III fully phased in	8.50%	8.50%
Tier 1, capital, required to be well-capitalized	$ 261,389	$ 227,397
Tier 1, ratio, required to be well-capitalized	8.00%	8.00%
Total capital	$ 512,801	$ 465,292
Total capital, ratio	15.70%	16.40%
Total capital, minimum capital required basel III phase in schedule	$ 322,651	$ 262,927
Total capital, ratio, minimum capital required basel iIII phase in schedule	9.88%	9.25%
Total capital, minimum capital required basel III fully phased in	$ 343,072	$ 298,458
Total capital, ratio, minimum capital required basel III fully phased in	10.50%	10.50%
Total capital, required to be well-capitalized	$ 326,736	$ 284,246
Total capital, ratio, required to be well-capitalized	10.00%	10.00%
Tier 1 Leverage Capital, Average Assets	$ 496,526	$ 446,154
Tier I Leverage Ratio, Average Assets	11.40%	11.00%
Tier 1 Leverage Capital, minimum capital required basel III phase in schedule	$ 174,833	$ 161,834
Tier 1 Leverage Ratio, minimum capital required basel III phase in schedule	4.00%	4.00%
Tier 1 Leverage Capital, minimum capital required basel III fully phased in	$ 174,833	$ 161,834
Tier 1 Leverage Ratio, minimum capital required basel III fully phased in	4.00%	4.00%
Tier 1 Leverage Capital Required to be Well Capitalized	$ 218,542	$ 202,293
Tier 1 Leverage Capital, Average Assets, Well Capitalized Ratio	5.00%	5.00%
City National
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital	$ 423,099	$ 338,105
CET1 ratio	13.10%	12.00%
CET1 capital, minimum capital required basel III phase in schedule	$ 206,676	$ 162,164
CET1 ratio, minimum capital required basel III phase in schedule	6.375%	5.75%
CET1 capital, minimum capital required basel III fully phased in	$ 226,938	$ 197,418
CET1 ratio, minimum capital required basel III fully phased in	7.00%	7.00%
CET1 capital, required to be well-capitalized	$ 210,728	$ 183,316
CET1 ratio, required to be well capitalized	6.50%	6.50%
Tier I capital	$ 423,099	$ 338,105
Tier I capital, ratio	13.10%	12.00%
Tier 1, capital, minimum capital required basel III phase in schedule	$ 255,306	$ 204,468
Tier 1, ratio, minimum capital required basel III phase in schedule	7.88%	7.25%
Tier 1, capital, minimum capital required basel III fully phased in	$ 275,568	$ 239,721
Tier 1, ratio, minimum capital required basel III fully phased in	8.50%	8.50%
Tier 1, capital, required to be well-capitalized	$ 259,358	$ 225,620
Tier 1, ratio, required to be well-capitalized	8.00%	8.00%
Total capital	$ 439,374	$ 357,243
Total capital, ratio	13.60%	12.70%
Total capital, minimum capital required basel III phase in schedule	$ 320,145	$ 260,873
Total capital, ratio, minimum capital required basel iIII phase in schedule	9.88%	9.25%
Total capital, minimum capital required basel III fully phased in	$ 340,408	$ 296,126
Total capital, ratio, minimum capital required basel III fully phased in	10.50%	10.50%
Total capital, required to be well-capitalized	$ 324,198	$ 282,025
Total capital, ratio, required to be well-capitalized	10.00%	10.00%
Tier 1 Leverage Capital, Average Assets	$ 423,099	$ 338,105
Tier I Leverage Ratio, Average Assets	9.80%	8.50%
Tier 1 Leverage Capital, minimum capital required basel III phase in schedule	$ 172,594	$ 159,625
Tier 1 Leverage Ratio, minimum capital required basel III phase in schedule	4.00%	4.00%
Tier 1 Leverage Capital, minimum capital required basel III fully phased in	$ 172,594	$ 159,625
Tier 1 Leverage Ratio, minimum capital required basel III fully phased in	4.00%	4.00%
Tier 1 Leverage Capital Required to be Well Capitalized	$ 215,742	$ 199,531
Tier 1 Leverage Capital, Average Assets, Well Capitalized Ratio	5.00%	5.00%