Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Revenues:
Revenue from contracts with customers	[1]	$ 532,144			$ 1,605,149
Principal transactions		83,152		$ 87,010	269,918		$ 299,570
Interest		169,760		117,862	461,915		327,766
Other income		6,127		9,558	18,557		25,508
Total revenues		786,810		738,794	2,343,632		2,172,512
Interest expense		48,468		17,625	112,200		50,165
Net revenues	[2]	738,342		721,169	2,231,432		2,122,347
Non-interest expenses:
Compensation and benefits		422,324		448,410	1,322,387		1,338,673
Occupancy and equipment rental		54,035		57,427	165,226		167,864
Communications and office supplies		33,330		34,650	103,468		102,686
Commissions and floor brokerage		11,338		11,232	30,798		33,187
Other operating expenses		76,785		61,311	231,122		209,581
Total non-interest expenses		597,812		613,030	1,853,001		1,851,991
Income from operations before income tax expense		140,530		108,139	378,431		270,356
Provision for income taxes		36,672		41,603	98,525		85,497
Net income		103,858		66,536	279,906		184,859
Preferred dividends		2,343		2,343	7,031		7,031
Net income available to common shareholders		$ 101,515		$ 64,193	$ 272,875		$ 177,828
Earnings per common share:
Basic		$ 1.41		$ 0.94	$ 3.80		$ 2.60
Diluted		$ 1.25		$ 0.79	$ 3.35		$ 2.21
Weighted-average number of common shares outstanding:
Basic		71,919		68,522	71,824		68,488
Diluted		81,484		80,881	81,425		80,562
Cash dividends declared per common share		$ 0.12		$ 0.10	$ 0.36		$ 0.10
Commissions [Member]
Revenues:
Revenue from contracts with customers		$ 158,016		$ 162,612	$ 490,693		$ 510,150
Investment Banking [Member]
Revenues:
Revenue from contracts with customers		169,012		181,904	506,437		494,017
Asset Management and Service Fees [Member]
Revenues:
Revenue from contracts with customers		$ 200,743	[1]	$ 179,848	$ 596,112	[1]	$ 515,501

[1] Excludes revenue included in the Other segment.

[2] No individual client accounted for more than 10 percent of total net revenues for the three and nine months ended September 30, 2018 or 2017.