Piper Sandler Companies (PIPR) 10-Q 31 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 18, 2013
Document and Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'PJC	'
Entity Registrant Name	'Piper Jaffray Companies	'
Entity Central Index Key	'0001230245	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	15,904,667

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Assets	'	'
Cash and cash equivalents	$13,961	$105,371
Cash and cash equivalents segregated for regulatory purposes	25,008	31,007
Receivables:	'	'
Customers	31,375	13,795
Brokers, dealers and clearing organizations	242,303	148,117
Securities purchased under agreements to resell	185,424	145,433
Financial instruments and other inventory positions owned	414,428	384,789
Financial instruments and other inventory positions owned and pledged as collateral	1,118,910	826,806
Total financial instruments and other inventory positions owned	1,533,338	1,211,595
Fixed assets (net of accumulated depreciation and amortization of $65,162 and $61,032, respectively)	15,279	15,089
Goodwill	210,800	196,844
Intangible assets (net of accumulated amortization of $30,097 and $23,876, respectively)	41,961	41,258
Other receivables	49,827	44,874
Other assets	143,418	129,697
Assets held for sale	0	4,653
Total assets	2,492,694	2,087,733
Liabilities and Shareholders’ Equity	'	'
Short-term financing	663,289	477,014
Variable rate senior notes	125,000	125,000
Payables:	'	'
Customers	40,778	42,007
Brokers, dealers and clearing organizations	126,352	60,155
Securities sold under agreements to repurchase	36,915	50,000
Financial instruments and other inventory positions sold, but not yet purchased	513,748	357,201
Accrued compensation	92,145	132,124
Other liabilities and accrued expenses	37,473	53,193
Liabilities held for sale	0	864
Total liabilities	1,635,700	1,297,558
Shareholders’ equity:	'	'
Common stock, $0.01 par value: Shares authorized: 100,000,000 at September 30, 2013 and December 31, 2012; Shares issued: 19,537,127 at September 30, 2013 and 19,530,359 at December 31, 2012; Shares outstanding: 14,403,523 at September 30, 2013 and 15,213,796 at December 31, 2012	195	195
Additional paid-in capital	739,693	754,566
Retained earnings	136,759	118,803
Less common stock held in treasury, at cost: 5,133,604 shares at September 30, 2013 and 4,316,563 shares at December 31, 2012	-169,965	-140,939
Accumulated other comprehensive income	683	667
Total common shareholders’ equity	707,365	733,292
Noncontrolling interests	149,629	56,883
Total shareholders’ equity	856,994	790,175
Total liabilities and shareholders’ equity	$2,492,694	$2,087,733

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Accumulated depreciation and amortization on fixed assets	$65,162	$61,032
Accumulated amortization on intangible assets	$30,097	$23,876
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	19,537,127	19,530,359
Common stock, shares outstanding	14,403,523	15,213,796
Common stock held in treasury, shares	5,133,604	4,316,563

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:	'	'	'	'
Investment banking	$62,373	$51,083	$155,581	$148,536
Institutional brokerage	37,218	58,719	101,038	134,006
Asset management	18,309	16,136	54,551	48,699
Interest	16,259	12,457	43,982	35,742
Other income	4,679	235	10,942	1,242
Total revenues	138,838	138,630	366,094	368,225
Interest expense	10,524	7,125	28,475	20,184
Net revenues	128,314	131,505	337,619	348,041
Non-interest expenses:	'	'	'	'
Compensation and benefits	79,426	78,070	210,531	209,467
Occupancy and equipment	6,509	6,057	18,869	19,671
Communications	5,778	5,276	16,040	16,112
Floor brokerage and clearance	2,109	1,825	6,506	5,934
Marketing and business development	5,447	4,259	16,384	14,982
Outside services	8,082	6,747	23,745	19,810
Restructuring and integration costs	3,823	0	3,823	3,642
Intangible asset amortization expense	2,899	1,736	6,221	5,208
Other operating expenses	2,181	2,183	1,939	6,986
Total non-interest expenses	116,254	106,153	304,058	301,812
Income from continuing operations before income tax expense	12,060	25,352	33,561	46,229
Income tax expense	2,886	10,194	10,130	12,048
Income from continuing operations	9,174	15,158	23,431	34,181
Discontinued operations:	'	'	'	'
Income/(loss) from discontinued operations, net of tax	-1,529	5,171	-3,921	-2,066
Net income	7,645	20,329	19,510	32,115
Net income applicable to noncontrolling interests	2,323	665	1,554	2,671
Net income applicable to Piper Jaffray Companies	5,322	19,664	17,956	29,444
Net income applicable to Piper Jaffray Companies’ common shareholders	4,826	16,840	16,163	25,151
Amounts applicable to Piper Jaffray Companies	'	'	'	'
Net income from continuing operations	6,851	14,493	21,877	31,510
Net income/(loss) from discontinued operations	($1,529)	$5,171	($3,921)	($2,066)
Earnings/(loss) per basic common share	'	'	'	'
Income from continuing operations	$0.42	$0.82	$1.29	$1.71
Loss from discontinued operations	($0.09)	$0.29	($0.23)	($0.11)
Earnings per basic common share	$0.33	$1.11	$1.06	$1.60
Earnings/(loss) per diluted common share	'	'	'	'
Income from continuing operations	$0.42	$0.82	$1.29	$1.71
Loss from discontinued operations	($0.09)	$0.29	($0.23)	($0.11)
Earnings per diluted common share	$0.33	$1.11	$1.06	$1.60
Weighted average number of common shares outstanding	'	'	'	'
Basic	14,621	15,210	15,271	15,736
Diluted	14,626	15,210	15,284	15,736

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]	'	'	'	'
Net income	$7,645	$20,329	$19,510	$32,115
Other comprehensive income/(loss), net of tax:	'	'	'	'
Adjustment to unrecognized pension cost	-38	0	-38	0
Foreign currency translation adjustment	175	122	54	131
Total other comprehensive income, net of tax	137	122	16	131
Comprehensive income	7,782	20,451	19,526	32,246
Comprehensive income applicable to noncontrolling interests	2,323	665	1,554	2,671
Comprehensive income applicable to Piper Jaffray Companies	$5,459	$19,786	$17,972	$29,575

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating Activities:	'	'
Net income	$19,510	$32,115
Adjustments to reconcile net income to net cash used in operating activities:	'	'
Depreciation and amortization of fixed assets	4,300	5,436
Deferred income taxes	5,933	6,056
Loss on sale of FAMCO	1,876	0
Share-based and deferred compensation	11,012	14,532
Amortization of intangible assets	6,221	5,751
Amortization of forgivable loans	4,827	6,077
Decrease/(increase) in operating assets:	'	'
Cash and cash equivalents segregated for regulatory purposes	5,999	-8,003
Receivables:	'	'
Customers	-17,580	6,600
Brokers, dealers and clearing organizations	-94,186	-44,790
Securities purchased under agreements to resell	-81,990	71,983
Net financial instruments and other inventory positions owned	-163,710	-389,491
Other receivables	-3,409	-17,827
Other assets	-13,021	-22,804
Payables:	'	'
Customers	-1,229	21,988
Brokers, dealers and clearing organizations	65,071	115,867
Securities sold under agreements to repurchase	36,915	0
Accrued compensation	-26,425	-7,084
Other liabilities and accrued expenses	-23,566	1,079
Decrease/(increase) in assets held for sale	605	-1,556
Increase/(decrease) in liabilities held for sale	-465	2,286
Net cash used in operating activities	-263,312	-201,785
Investing Activities:	'	'
Business acquisitions, net of cash acquired	-24,726	0
Sale of FAMCO	250	0
Purchases of fixed assets, net	-3,257	-420
Net cash used in investing activities	-27,733	-420
Financing Activities:	'	'
Increase in short-term financing	186,275	277,771
Decrease in bank syndicated financing	0	-31,512
Decrease in securities sold under agreements to repurchase	-8,001	-59,080
Increase in noncontrolling interests	91,192	11,080
Repurchase of common stock	-69,947	-42,514
Excess tax benefit from share-based compensation	39	0
Net cash provided by financing activities	199,558	155,745
Currency adjustment:	'	'
Effect of exchange rate changes on cash	77	-10
Net decrease in cash and cash equivalents	-91,410	-46,470
Cash and cash equivalents at beginning of period	105,371	85,024
Cash and cash equivalents at end of period	13,961	38,554
Supplemental disclosure of cash flow information –	'	'
Interest	27,694	20,756
Income taxes	2,870	-1,784
Non-cash financing activities –	'	'
Issuance of common stock for retirement plan obligations: 96,049 shares and 165,241 for the nine months ended September 30, 2013 and 2012, respectively	3,939	3,814
Issuance of restricted common stock for annual equity award: 431,582 shares and 487,181 shares for the nine months ended September 30, 2013 and 2012, respectively	$17,699	$11,244

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Statement of Cash Flows [Abstract]	'	'
Stock Issued During Period, Shares, Treasury Stock Reissued	96,049	165,241
Number of restricted common stock issued for annual equity award	431,582	487,181

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Basis of Presentation	'
	Organization and Basis of Presentation
	Organization
	Piper Jaffray Companies is the parent company of Piper Jaffray & Co. (“Piper Jaffray”), a securities broker dealer and investment banking firm; Piper Jaffray Ltd., a firm providing securities brokerage and mergers and acquisitions services in Europe headquartered in London, England; Advisory Research, Inc. (“ARI”), which provides asset management services to separately managed accounts, closed-end and open-end funds and partnerships; Piper Jaffray Investment Group Inc., which consists of entities providing alternative asset management services; Piper Jaffray Financial Products Inc., Piper Jaffray Financial Products II Inc. and Piper Jaffray Financial Products III Inc., entities that facilitate derivative transactions; and other immaterial subsidiaries. Piper Jaffray Companies and its subsidiaries (collectively, the “Company”) operate in two reporting segments: Capital Markets and Asset Management. A summary of the activities of each of the Company’s business segments is as follows:
	Capital Markets
	The Capital Markets segment provides institutional sales, trading and research services and investment banking services. Institutional sales, trading and research services focus on the trading of equity and fixed income products with institutions, government and non-profit entities. Revenues are generated through commissions and sales credits earned on equity and fixed income institutional sales activities, net interest revenues on trading securities held in inventory, and profits and losses from trading these securities. Investment banking services include management of and participation in underwritings, merger and acquisition services and public finance activities. Revenues are generated through the receipt of advisory and financing fees. Also, the Company generates revenue through strategic trading activities, which focus on proprietary investments in municipal bonds, mortgage-backed securities, equity securities and merchant banking activities, which involve equity or debt investments in late stage private companies. As certain of these efforts have matured and an investment process has been developed, the Company has created alternative asset management funds in merchant banking and municipal securities in order to invest firm capital as well as seek capital from outside investors. The Company receives management and performance fees for managing these funds.
	As discussed in Note 5, the Company discontinued its Hong Kong capital markets business in 2012.
	Asset Management
	The Asset Management segment provides traditional asset management services with product offerings in equity securities and master limited partnerships to institutions and individuals. Revenues are generated in the form of management and performance fees. Revenues are also generated through investments in the partnerships and funds that the Company manages.
	As discussed in Note 5, Fiduciary Asset Management, LLC (“FAMCO”) was sold on April 30, 2013.
	Basis of Presentation
	The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of Piper Jaffray Companies, its wholly owned subsidiaries, and all other entities in which the Company has a controlling financial interest. Noncontrolling interests represent equity interests in consolidated entities that are not attributable, either directly or indirectly, to Piper Jaffray Companies. Noncontrolling interests include the minority equity holders’ proportionate share of the equity in a municipal bond fund, merchant banking fund and private equity investment vehicles. All material intercompany balances have been eliminated.
	The preparation of financial statements and related disclosures in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates and assumptions are based on the best information available, actual results could differ from those estimates.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Refer to the Company's Annual Report on Form 10-K for the year ended December 31, 2012 for a full description of the Company's significant accounting policies.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2013
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	Adoption of New Accounting Standards
	Disclosures about Offsetting Assets and Liabilities
	In December 2011, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2011-11, “Disclosures about Offsetting Assets and Liabilities,” (“ASU 2011-11”) amending FASB Accounting Standards Codification Topic 210, “Balance Sheet.” The amended guidance requires an entity to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. In January 2013, the FASB issued ASU No. 2013-01, “Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities,” (“ASU 2013-01”) to limit the scope of ASU 2011-11 to derivatives, repurchase agreements, and securities lending arrangements. ASU 2011-11 and ASU 2013-01 were effective for the Company as of January 1, 2013. The adoption of ASU 2011-11 and ASU 2013-01 did not impact the Company’s results of operations or financial position, but did impact the Company’s disclosures about the offsetting of certain assets and liabilities, and related arrangements.
	Indefinite-Lived Intangible Assets
	In July 2012, the FASB issued ASU No. 2012-02, “Testing Indefinite-Lived Intangible Assets for Impairment,” (“ASU 2012-02”) amending FASB Accounting Standards Codification Topic 350, “Intangibles - Goodwill and Other.” The amended guidance permits companies to first assess qualitative factors in determining whether the fair value of an indefinite-lived intangible asset is less than its carrying amount. ASU 2012-02 was effective for annual and interim indefinite-lived intangible asset impairment tests performed by the Company for the fiscal year beginning as of January 1, 2013. The adoption of ASU 2012-02 did not impact the Company's results of operations or financial position.
	Future Adoption of New Accounting Standards
	Investment Companies
	In June 2013, the FASB issued ASU No. 2013-08, “Financial Services - Investment Companies (Topic 946): Amendments to the Scope, Measurement, and Disclosure Requirements,” (“ASU 2013-08”) amending FASB Accounting Standards Codification Topic 946, “Financial Services - Investment Companies” (“ASC 946”). The amended guidance changes the approach to the investment company assessment in ASC 946, clarifies the characteristics of an investment company and requires new disclosures for investment company financial statements. ASU 2013-08 is effective for interim and annual periods beginning after December 15, 2013. The adoption of ASU 2013-08 is not expected to have an impact on the Company's results of operations, financial position or disclosures.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	On July 12, 2013, the Company completed the purchase of Seattle-Northwest Securities Corporation ("Seattle-Northwest"), a Seattle-based investment bank and broker dealer focused on public finance in the Northwest region of the U.S. The purchase was completed pursuant to the Agreement and Plan of Merger dated April 16, 2013. The acquisition of Seattle-Northwest supports the Company's strategy to grow its public finance business.
	On July 16, 2013, the Company completed the purchase of Edgeview Partners, L.P. ("Edgeview"), a middle-market equity advisory firm specializing in mergers and acquisitions. The purchase was completed pursuant to the Unit Purchase Agreement dated June 17, 2013. The acquisition of Edgeview further strengthens the Company's mergers and acquisitions leadership in the middle market and adds resources dedicated to the private equity community.
	The Company paid $32.7 million in cash for Seattle-Northwest and Edgeview, which represented the fair values as of the respective acquisition dates. The Company also entered into acquisition-related compensation arrangements of $14.3 million which consisted of cash, restricted stock and restricted mutual fund shares ("MFRS Awards") of registered funds managed by the Company's asset management business. Compensation expense related to these arrangements will be amortized on a straight-line basis over the requisite service period of two to five years (a weighted average service period of 4.3 years).
	These acquisitions were accounted for pursuant to FASB Accounting Standards Codification Topic 805, "Business Combinations." Accordingly, the purchase price of each acquisition was allocated to the acquired assets and liabilities assumed based on their estimated fair values as of the respective acquisition dates. The excess of the purchase price over the net assets acquired was allocated between goodwill and intangible assets within the Capital Markets segment. The Company recorded $14.0 million of goodwill on the consolidated statement of financial condition, of which $8.9 million is expected to be deductible for income tax purposes. The final goodwill recorded on the Company's consolidated statement of financial condition may differ from that reflected herein as a result of measurement period adjustments. In management's opinion, the goodwill represents the reputation and expertise of Seattle-Northwest and Edgeview in their respective business lines.
	Identifiable intangible assets purchased by the Company consisted of customer relationships and non-competition agreements with acquisition-date fair values currently estimated to be $6.2 million and $0.7 million, respectively. The Company anticipates finalizing the fair value of intangible assets in the fourth quarter of 2013. Transaction costs of $0.9 million were incurred in the three and nine months ended September 30, 2013, respectively, and are included in restructuring and integration costs within continuing operations on the consolidated statement of operations.
	The following table summarizes the estimated fair values of assets acquired and liabilities assumed at the respective dates of acquisition:
	(Dollars in thousands)
	Assets
	Cash and cash equivalents		$	8,014
	Financial instruments and other inventory positions owned		24,074
	Fixed assets		1,247
	Goodwill		13,956
	Intangible assets		6,924
	Other receivables		2,280
	Other assets		6,642
	Total assets acquired		63,137
	Liabilities
	Payables		1,126
	Financial instruments and other inventory positions sold, but not yet purchased		22,588
	Accrued compensation		1,469
	Other liabilities and accrued expenses		5,214
	Total liabilities assumed		30,397
	Net assets acquired		$	32,740
	Seattle-Northwest and Edgeview results of operations have been included in the Company's consolidated financial statements prospectively from their respective dates of acquisition. These acquisitions have been fully integrated with the Company's existing operations. Accordingly, post-acquisition revenues and net income are not discernible. The following unaudited pro forma financial data assumes the acquisitions had occurred at the beginning of the comparable prior periods presented. Pro forma results have been prepared by adjusting the Company's historical results from continuing operations to include Seattle-Northwest and Edgeview results of operations adjusted for the following changes: depreciation and amortization expenses were adjusted to account for acquisition-date fair value adjustments of fixed assets and intangible assets; compensation and benefits expenses were adjusted to reflect excess partner distributions as compensation expense; and the income tax effect of applying the Company's statutory tax rates to Seattle-Northwest and Edgeview results of operations. The consolidated Company's unaudited pro forma information presented does not necessarily reflect the results of operations that would have resulted had the acquisitions been completed at the beginning of the applicable periods presented, does not contemplate anticipated operational efficiencies of the combined entities, nor does it indicate the results of operations in future periods.
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
	(Dollars in thousands)	2013			2012		2013		2012
	Net revenues	$	132,773		$	139,877	$	353,728	$	374,646
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,948		$	14,187	$	20,631	$	30,930

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	Discontinued Operations
	The Company's Hong Kong capital markets business ceased operations as of September 30, 2012. In accordance with the provisions of FASB Accounting Standards Codification Topic 205-20, “Discontinued Operations,” the results from this business, previously reported in the Capital Markets segment, have been classified as discontinued operations for all periods presented.
	The components of discontinued operations for the Hong Kong capital markets business are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues	$	—		$	2,674		$	—		$	6,625
	Restructuring expenses	—			11,057			—			11,057
	Other expenses	158			5,843			517			16,550
	Total non-interest expenses	158			16,900			517			27,607
	Loss from discontinued operations before income tax benefit	(158		)	(14,226		)	(517		)	(20,982		)
	Income tax benefit	(61		)	(21,029		)	(151		)	(20,969		)
	Income/(loss) from discontinued operations, net of tax	$	(97	)	$	6,803		$	(366	)	$	(13	)
	On April 30, 2013, the Company completed the sale of FAMCO for consideration of $4.0 million under a previously announced definitive agreement. The sale consideration of $4.0 million consisted of $0.3 million in cash and a $3.7 million note receivable from the buyer. FAMCO's results, previously reported in the Asset Management segment, have been presented as discontinued operations for all periods presented and the related assets and liabilities were classified as held for sale as of December 31, 2012. The disposal group primarily consisted of intangible assets, other receivables and accrued compensation. As part of the sale, the Company indemnified the buyer against certain costs and obligations associated with an administrative proceeding the SEC is pursuing against former FAMCO employees and related matters. As of September 30, 2013, $4.7 million related to this indemnification was included within other liabilities and accrued expenses on the consolidated statements of financial condition. The potential amount of future payments that the Company could be required to make with respect to the administrative proceeding against the employees pursuant to the terms of the definitive sale agreement is not limited.
	The components of discontinued operations for FAMCO are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues	$	—		$	1,453		$	1,716		$	4,228
	Total non-interest expenses	2,365			4,090			4,486			6,962
	Loss from discontinued operations before income tax benefit	(2,365		)	(2,637		)	(2,770		)	(2,734		)
	Income tax benefit	(933		)	(1,005		)	(1,091		)	(681		)
	Loss from discontinued operations	(1,432		)	(1,632		)	(1,679		)	(2,053		)
	Loss on sale, net of tax	—			—			(1,876		)	—
	Loss from discontinued operations, net of tax	$	(1,432	)	$	(1,632	)	$	(3,555	)	$	(2,053	)

Financial_Instruments_and_Othe

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased	9 Months Ended
	Sep. 30, 2013
Disclosure Financial Instruments And Other Inventory Positions Owned And Financial Instruments And Other Inventory Positions Sold But Not Yet Purchased [Abstract]	'
Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased	'
	Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased
	Financial instruments and other inventory positions owned and financial instruments and other inventory positions sold, but not yet purchased were as follows:
		September 30,				December 31,
	(Dollars in thousands)	2013				2012
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	28,203			$	16,478
	Convertible securities	73,216				44,978
	Fixed income securities	22,106				33,668
	Municipal securities:
	Taxable securities	250,608				164,059
	Tax-exempt securities	560,403				418,189
	Short-term securities	99,522				68,328
	Asset-backed securities	157,059				116,195
	U.S. government agency securities	303,359				304,259
	U.S. government securities	233				4,966
	Derivative contracts	38,629				40,475
	Total financial instruments and other inventory positions owned	1,533,338				1,211,595
	Less noncontrolling interests (1)	(276,379		)		(103,480		)
		$	1,256,959			$	1,108,115
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	58,599			$	27,090
	Convertible securities	198				1,015
	Fixed income securities	17,022				19,314
	Municipal securities:
	Short-term securities	—				60
	U.S. government agency securities	79,135				73,724
	U.S. government securities	353,321				231,043
	Derivative contracts	5,473				4,955
	Total financial instruments and other inventory positions sold, but not yet purchased	513,748				357,201
	Less noncontrolling interests (2)	(66,047		)		(27,308		)
		$	447,701			$	329,893
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $104.1 million and $43.8 million of taxable municipal securities, $168.2 million and $58.0 million of tax-exempt municipal securities, and $4.1 million and $1.7 million of derivative contracts as of September 30, 2013 and December 31, 2012, respectively.
	-2	Noncontrolling interests attributable to third party ownership interests in a consolidated municipal bond fund consist of $66.0 million and $27.3 million of U.S. government securities as of September 30, 2013 and December 31, 2012, respectively.
	At September 30, 2013 and December 31, 2012, financial instruments and other inventory positions owned in the amount of $1.1 billion and $826.8 million, respectively, had been pledged as collateral for short-term financings and repurchase agreements.
	Financial instruments and other inventory positions sold, but not yet purchased represent obligations of the Company to deliver the specified security at the contracted price, thereby creating a liability to purchase the security in the market at prevailing prices. The Company is obligated to acquire the securities sold short at prevailing market prices, which may exceed the amount reflected on the consolidated statements of financial condition. The Company economically hedges changes in the market value of its financial instruments and other inventory positions owned using inventory positions sold, but not yet purchased, interest rate derivatives, credit default swap index contracts, futures and exchange-traded options.
	Derivative Contract Financial Instruments
	The Company uses interest rate swaps, interest rate locks and credit default swap index contracts to facilitate customer transactions and as a means to manage risk in certain inventory positions. The following describes the Company’s derivatives by the type of transaction or security the instruments are economically hedging.
	Customer matched-book derivatives: The Company enters into interest rate derivative contracts in a principal capacity as a dealer to satisfy the financial needs of its customers.  The Company simultaneously enters into  an interest rate  derivative  contract with a third party for the same notional amount to hedge the interest rate and credit risk of the initial client interest rate derivative contract. In certain limited instances, the Company has only hedged interest rate risk with a third party, and retains uncollateralized credit risk as described below. The instruments use interest rates based upon either the London Interbank Offer Rate (“LIBOR”) index or the Securities Industry and Financial Markets Association (“SIFMA”) index.
	Trading securities derivatives: The Company enters into interest rate derivative contracts to hedge interest rate and market value risks associated with its fixed income securities. The instruments use interest rates based upon either the Municipal Market Data (“MMD”) index, LIBOR or the SIFMA index. The Company also enters into credit default swap index contracts to hedge credit risk associated with its taxable fixed income securities.
	The following table presents the total absolute notional contract amount associated with the Company’s outstanding derivative instruments:
	(Dollars in thousands)				September 30,				December 31,
	Transaction Type or Hedged Security		Derivative Category		2013				2012
	Customer matched-book		Interest rate derivative contract		$	5,345,918			$	5,569,096
	Trading securities		Interest rate derivative contract		270,500				244,250
	Trading securities		Credit default swap index contract		494,233				230,650
					$	6,110,651			$	6,043,996
	The Company’s interest rate derivative contracts and credit default swap index contracts do not qualify for hedge accounting, therefore, unrealized gains and losses are recorded on the consolidated statements of operations. The following table presents the Company’s unrealized gains/(losses) on derivative instruments:
					Three Months Ended								Nine Months Ended
	(Dollars in thousands)				September 30,								September 30,
	Derivative Category		Operations Category		2013				2012				2013			2012
	Interest rate derivative contract		Investment banking		$	(483	)		$	(440	)		$	(1,132	)	$	(2,045	)
	Interest rate derivative contract		Institutional brokerage		(16,532		)		(4,735		)		4,930			(8,003		)
	Credit default swap index contract		Institutional brokerage		(1,918		)		(1,782		)		(650		)	(1,422		)
					$	(18,933	)		$	(6,957	)		$	3,148		$	(11,470	)
	The gross fair market value of all derivative instruments and their location on the Company’s consolidated statements of financial condition prior to counterparty netting are shown below by asset or liability position (1):
	(Dollars in thousands)				Asset Value at						Liability Value at
					September 30,						September 30,
	Derivative Category		Financial Condition Location		2013				Financial Condition Location		2013
	Interest rate derivative contract		Financial instruments and other inventory positions owned		$	402,823			Financial instruments and other inventory positions sold,  but not yet purchased		$	375,806
	Credit default swap index contract		Financial instruments and other inventory positions owned		11,187				Financial instruments and other inventory positions sold,  but not yet purchased		7,185
					$	414,010					$	382,991
-1	Amounts are disclosed at gross fair value in accordance with the requirements of FASB Accounting Standards Codification Topic 815, "Derivatives and Hedging" ("ASC 815").
Derivatives are reported on a net basis by counterparty (i.e., the net payable or receivable for derivative assets and liabilities for a given counterparty) when a legal right of offset exists and on a net basis by cross product when applicable provisions are stated in master netting agreements. Cash collateral received or paid is netted on a counterparty basis, provided a legal right of offset exists.
Credit risk associated with the Company’s derivatives is the risk that a derivative counterparty will not perform in accordance with the terms of the applicable derivative contract. Credit exposure associated with the Company’s derivatives is driven by uncollateralized market movements in the fair value of the contracts with counterparties and is monitored regularly by the Company’s financial risk committee. The Company considers counterparty credit risk in determining derivative contract fair value. The majority of the Company’s  derivative contracts are substantially collateralized by its counterparties, who  are major  financial institutions. The Company has a limited number of counterparties who are not required to post collateral. Based on market movements, the uncollateralized amounts representing the fair value of the derivative contract can become material, exposing the Company to the credit risk of these counterparties. As of September 30, 2013, the Company had $23.6 million of uncollateralized credit exposure with these counterparties (notional contract amount of $201.7 million), including $11.1 million of uncollateralized credit exposure with one counterparty.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	Based on the nature of the Company’s business and its role as a “dealer” in the securities industry or as a manager of alternative asset management funds, the fair values of its financial instruments are determined internally. The Company’s processes are designed to ensure that the fair values used for financial reporting are based on observable inputs wherever possible. In the event that observable inputs are not available, unobservable inputs are developed based on an evaluation of all relevant empirical market data, including prices evidenced by market transactions, interest rates, credit spreads, volatilities and correlations and other security-specific information. Valuation adjustments related to illiquidity or counterparty credit risk are also considered. In estimating fair value, the Company may utilize information provided by third-party pricing vendors to corroborate internally-developed fair value estimates.
	The Company employs specific control processes to determine the reasonableness of the fair value of its financial instruments. The Company’s processes are designed to ensure that the internally estimated fair values are accurately recorded and that the data inputs and the valuation techniques used are appropriate, consistently applied, and that the assumptions are reasonable and consistent with the objective of determining fair value. Individuals outside of the trading departments perform independent pricing verification reviews as of each reporting date. The Company has established parameters which set forth when the fair value of securities are independently verified. The selection parameters are generally based upon the type of security, the level of estimation risk of a security, the materiality of the security to the Company’s financial statements, changes in fair value from period to period, and other specific facts and circumstances of the Company’s securities portfolio. In evaluating the initial internally-estimated fair values made by the Company’s traders, the nature and complexity of securities involved (e.g., term, coupon, collateral, and other key drivers of value), level of market activity for securities, and availability of market data are considered. The independent price verification procedures include, but are not limited to, analysis of trade data (both internal and external where available), corroboration to the valuation of positions with similar characteristics, risks and components, or comparison to an alternative pricing source, such as a discounted cash flow model. The Company’s valuation committee, comprised of members of senior management, provides oversight and overall responsibility for the internal control processes and procedures related to fair value measurements.
	The following is a description of the valuation techniques used to measure fair value.
	Cash Equivalents
	Cash equivalents include highly liquid investments with original maturities of 90 days or less. Actively traded money market funds are measured at their net asset value and classified as Level I.
	Financial Instruments and Other Inventory Positions Owned
	The Company records financial instruments and other inventory positions owned and financial instruments and other inventory positions sold, but not yet purchased at fair value on the consolidated statements of financial condition with unrealized gains and losses reflected on the consolidated statements of operations.
	Equity securities – Exchange traded equity securities are valued based on quoted prices from the exchange for identical assets or liabilities as of the period-end date. To the extent these securities are actively traded and valuation adjustments are not applied, they are categorized as Level I. Non-exchange traded equity securities (principally hybrid preferred securities) are measured primarily using broker quotations, prices observed for recently executed market transactions and internally-developed fair value estimates based on observable inputs and are categorized within Level II of the fair value hierarchy.
	Convertible securities – Convertible securities are valued based on observable trades, when available. Accordingly, these convertible securities are categorized as Level II. When  observable price quotations are not available, fair value is determined using model-based valuation techniques with observable market inputs, such as specific company stock price and volatility, and unobservable inputs such as option adjusted spreads over the U.S. treasury securities curve. These instruments are categorized as Level III.
	Corporate fixed income securities – Fixed income securities include corporate bonds which are valued based on recently executed market transactions of comparable size, internally-developed fair value estimates based on observable inputs, or broker quotations. Accordingly, these corporate bonds are categorized as Level II. When observable price quotations or certain observable inputs are not available, fair value is determined using model-based valuation techniques with observable inputs such as specific security contractual terms and yield curves, and unobservable inputs such as credit spreads over U.S. treasury securities. Corporate bonds measured using model-based valuation techniques are categorized as Level III.
	Taxable municipal securities – Taxable municipal securities are valued using recently executed observable trades or market price quotations and therefore are generally categorized as Level II.
	Tax-exempt municipal securities – Tax-exempt municipal securities are valued using recently executed observable trades or market price quotations and therefore are generally categorized as Level II. Certain illiquid tax-exempt municipal securities are valued using market data for comparable securities (maturity and sector) and management judgment to infer an appropriate current yield or other model-based valuation techniques deemed appropriate by management based on the specific nature of the individual security and are therefore categorized as Level III.
	Short-term municipal securities – Short-term municipal securities include auction rate securities, variable rate demand notes, and other short-term municipal securities. Variable rate demand notes and other short-term municipal securities are valued using recently executed observable trades or market price quotations and therefore are generally categorized as Level II. Auction rate securities with limited liquidity are categorized as Level III and are valued using discounted cash flow models with unobservable inputs such as the Company’s expectations of recovery rate on the securities.
	Asset-backed securities – Asset-backed securities are valued using observable trades, when available. Certain asset-backed securities are valued using models where inputs to the model are directly observable in the market, or can be derived principally from or corroborated by observable market data. These asset-backed securities are categorized as Level II. Other asset-backed securities, which are principally collateralized by residential mortgages, have experienced low volumes of executed transactions resulting in less observable transaction data. Certain asset-backed securities collateralized by residential mortgages are valued using cash flow models that utilize unobservable inputs including credit default rates, prepayment rates, loss severity and valuation yields. As judgment is used to determine the range of these inputs, these asset-backed securities are categorized as Level III.
	U.S. government agency securities – U.S. government agency securities include agency debt bonds and mortgage bonds. Agency debt bonds are valued by using either direct price quotes or price quotes for comparable bond securities and are categorized as Level II. Mortgage bonds include bonds secured by mortgages, mortgage pass-through securities, agency collateralized mortgage-obligation (“CMO”) securities and agency interest-only securities. Mortgage pass-through securities, CMO securities and interest-only securities are valued using recently executed observable trades or other observable inputs, such as prepayment speeds and therefore are generally categorized as Level II. Mortgage bonds are valued using observable market inputs, such as market yields ranging from 140-200 basis points (“bps”) on spreads over U.S. treasury securities, or models based upon prepayment expectations ranging from 200-350 Public Securities Association (“PSA”) prepayment levels. These securities are categorized as Level II.
	U.S. government securities – U.S. government securities include highly liquid U.S. treasury securities which are generally valued using quoted market prices and therefore categorized as Level I. The Company does not transact in securities of countries other than the U.S. government.
	Derivatives – Derivative contracts include interest rate and basis swaps, forward purchase agreements, interest rate locks, futures and credit default swap index contracts. These instruments derive their value from underlying assets, reference rates, indices or a combination of these factors. The majority of the Company’s interest rate derivative contracts, including both interest rate swaps and interest rate locks, are valued using market standard pricing models based on the net present value of estimated future cash flows. The valuation models used do not involve material subjectivity as the methodologies do not entail significant judgment and the pricing inputs are market observable, including contractual terms, yield curves and measures of volatility. These instruments are classified as Level II within the fair value hierarchy. Certain interest rate locks transact in less active markets and were valued using valuation models that used the previously mentioned observable inputs and certain unobservable inputs that required significant judgment, such as the premium over the MMD curve. These instruments are classified as Level III. The Company’s credit default swap index contracts are valued using market price quotations and are classified as Level II.
	Investments
	The Company’s investments valued at fair value include equity investments in private companies, investments in public companies, investments in registered mutual funds, and warrants of public or private companies. These investments are included in other assets on the consolidated statements of financial condition. Exchange traded direct equity investments in public companies and registered mutual funds are valued based on quoted prices on active markets and classified as Level I. Company-owned warrants, which have a cashless exercise option, are valued based upon the Black-Scholes option-pricing model and certain unobservable inputs. The Company applies a liquidity discount to the value of its warrants in public and private companies. For warrants in private companies, valuation adjustments, based upon management’s judgment, are made to account for differences between the measured security and the stock volatility factors of comparable companies. Company-owned warrants are reported as Level III assets. Equity securities in private companies are valued based on an assessment of each underlying security, considering rounds of financing, third-party transactions and market-based information, including comparable company transactions, trading multiples and changes in market outlook, among other factors. These securities are generally categorized as Level III.
	Fair Value Option – The fair value option permits the irrevocable fair value option election on an instrument-by-instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument. The fair value option was elected for certain merchant banking and other investments at inception to reflect economic events in earnings on a timely basis. At September 30, 2013, $15.1 million in merchant banking and other equity investments, included within other assets on the consolidated statements of financial condition, are accounted for at fair value and are classified as Level III assets. The gains from fair value changes included in earnings as a result of electing to apply the fair value option to certain financial assets were $9.5 million and $2.3 million for the nine months ended September 30, 2013 and 2012, respectively.
	The following table summarizes quantitative information about the significant unobservable inputs used in the fair value measurement of the Company’s Level III financial instruments as of September 30, 2013:
		Valuation					Weighted
		Technique		Unobservable Input	Range		Average
	Assets:
	Financial instruments and other inventory positions owned:
	Municipal securities:
	Tax-exempt securities	Discounted cash flow		Debt service coverage ratio (2)	5 - 69%		22.20%
	Short-term securities	Discounted cash flow		Expected recovery rate  (% of par) (2)	77 - 80%		79.60%
	Asset-backed securities:
	Collateralized by residential mortgages	Discounted cash flow		Credit default rates (3)	1 - 9%		5.40%
				Prepayment rates (4)	1 - 9%		4.90%
				Loss severity (3)	45 - 100%		66.90%
				Valuation yields (3)	5 - 7%		5.80%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	5 - 30 bps		11.4 bps
	Investments:
	Warrants in private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 35%		30.20%
				Stock volatility factors of comparable companies (2)	39 - 127%		52.20%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 3 times		2.8 times
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	12 - 31 bps		23.2 bps
	Sensitivity of the fair value to changes in unobservable inputs:
	-1	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly lower/(higher) fair value measurement.
	-2	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly higher/(lower) fair value measurement.
	-3	Significant changes in any of these inputs in isolation could result in a significantly different fair value. Generally, a change in the assumption used for credit default rates is accompanied by a directionally similar change in the assumption used for the loss severity and a directionally inverse change in the assumption for valuation yields.
	-4	The potential impact of changes in prepayment rates on fair value is dependent on other security-specific factors, such as the par value and structure. Changes in the prepayment rates may result in directionally similar or directionally inverse changes in fair value depending on whether the security trades at a premium or discount to the par value.
	The following table summarizes the valuation of the Company’s financial instruments by pricing observability levels defined in FASB Accounting Standards Codification Topic 820, "Fair Value Measurement" ("ASC 820") as of September 30, 2013:
											Counterparty
											and Cash
											Collateral
	(Dollars in thousands)	Level I			Level II			Level III			Netting (1)			Total
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	25,289		$	2,914		$	—		$	—		$	28,203
	Convertible securities	—			73,216			—			—			73,216
	Fixed income securities	—			22,006			100			—			22,106
	Municipal securities:
	Taxable securities	—			250,608			—			—			250,608
	Tax-exempt securities	—			558,970			1,433			—			560,403
Short-term securities	—			98,866			656			—			99,522
Asset-backed securities	—			17			157,042			—			157,059
U.S. government agency securities	—			303,359			—			—			303,359
U.S. government securities	233			—			—			—			233
Derivative contracts	—			405,939			8,071			(375,381		)	38,629
Total financial instruments and other inventory positions owned:	25,522			1,715,895			167,302			(375,381		)	1,533,338
Cash equivalents	1,670			—			—			—			1,670
Investments	13,417			576			45,579			—			59,572
Total assets	$	40,609		$	1,716,471		$	212,881		$	(375,381	)	$	1,594,580
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	56,928		$	1,671		$	—		$	—		$	58,599
Convertible securities	—			198			—			—			198
Fixed income securities	—			17,022			—			—			17,022
U.S. government agency securities	—			79,135			—			—			79,135
U.S. government securities	353,321			—			—			—			353,321
Derivative contracts	—			376,410			6,581			(377,518		)	5,473
Total financial instruments and other inventory positions sold, but not yet purchased:	$	410,249		$	474,436		$	6,581		$	(377,518	)	$	513,748
-1	Represents cash collateral and the impact of netting on a counterparty basis. The Company had no securities posted as collateral to its counterparties.
The following table summarizes the valuation of the Company’s financial instruments by pricing observability levels defined in ASC 820 as of December 31, 2012:
										Counterparty
										and Cash
										Collateral
(Dollars in thousands)	Level I			Level II			Level III			Netting (1)			Total
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Equity securities	$	3,180		$	13,298		$	—		$	—		$	16,478
Convertible securities	—			44,978			—			—			44,978
Fixed income securities	—			33,668			—			—			33,668
Municipal securities:
Taxable securities	—			164,059			—			—			164,059
Tax-exempt securities	—			416,760			1,429			—			418,189
Short-term securities	—			67,672			656			—			68,328
Asset-backed securities	—			24			116,171			—			116,195
U.S. government agency securities	—			304,259			—			—			304,259
U.S. government securities	4,966			—			—			—			4,966
Derivative contracts	—			595,486			827			(555,838		)	40,475
Total financial instruments and other inventory positions owned:	8,146			1,640,204			119,083			(555,838		)	1,211,595
Cash equivalents	51,346			—			—			—			51,346
Investments	5,810			—			33,245			—			39,055
Total assets	$	65,302		$	1,640,204		$	152,328		$	(555,838	)	$	1,301,996
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	25,362		$	1,728		$	—		$	—		$	27,090
Convertible securities	—			1,015			—			—			1,015
Fixed income securities	—			19,314			—			—			19,314
Municipal securities:
Short-term securities	—			60			—			—			60
U.S. government agency securities	—			73,724			—			—			73,724
U.S. government securities	231,043			—			—			—			231,043
Derivative contracts	—			569,764			5,218			(570,027		)	4,955
Total financial instruments and other inventory positions sold, but not yet purchased:	$	256,405		$	665,605		$	5,218		$	(570,027	)	$	357,201
-1	Represents cash collateral and the impact of netting on a counterparty basis. The Company had no securities posted as collateral to its counterparties.
The Company’s Level III assets were $212.9 million and $152.3 million, or 13.4 percent and 11.7 percent of financial instruments measured at fair value at September 30, 2013 and December 31, 2012, respectively. The value of transfers between levels are recognized at the beginning of the reporting period. There were $0.9 million of transfers of financial assets from Level III to Level II during the three months ended September 30, 2013, related to investments and convertible securities for which recent trade activity was observed and valuation inputs became observable. There were $0.6 million of transfers of financial assets from Level III to Level II during the nine months ended September 30, 2013, related to investments for which recent trade activity was observed and valuation inputs became observable. There were no other transfers between Level I, Level II or Level III for the three and nine months ended September 30, 2013, respectively.
The following tables summarize the changes in fair value associated with Level III financial instruments during the three months ended September 30, 2013 and 2012:
	Balance at															Realized			Unrealized			Balance at
	June 30,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2013			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2013
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Convertible securities	$	1,308		$	—		$	(1,615	)	$	—		$	(251	)	$	839		$	(281	)	$	—
Fixed income securities	100			—			—			—			—			—			—			100
Municipal securities:
Tax-exempt securities	1,433			—			—			—			—			—			—			1,433
Short-term securities	656			—			—			—			—			—			—			656
Asset-backed securities	151,396			99,763			(97,246		)	—			—			(276		)	3,405			157,042
Derivative contracts	17,879			—			(12,337		)	—			—			12,337			(9,808		)	8,071
Total financial instruments and other inventory positions owned:	172,772			99,763			(111,198		)	—			(251		)	12,900			(6,684		)	167,302
Investments	53,567			—			(10,356		)	—			(619		)	5,942			(2,955		)	45,579
Total assets	$	226,339		$	99,763		$	(121,554	)	$	—		$	(870	)	$	18,842		$	(9,639	)	$	212,881
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	254		$	(223	)	$	—		$	—		$	—		$	223		$	6,327		$	6,581
Total financial instruments and other inventory positions sold, but not yet purchased:	$	254		$	(223	)	$	—		$	—		$	—		$	223		$	6,327		$	6,581
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
	Balance at															Realized			Unrealized			Balance at
	June 30,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2012			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2012
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Convertible securities	$	3,681		$	27,142		$	(21,249	)	$	—		$	—		$	2,051		$	836		$	12,461
Municipal securities:
Tax-exempt securities	2,373			20			(1,102		)	266			—			(584		)	553			1,526
Short-term securities	394			—			—			—			—			—			42			436
Asset-backed securities	89,871			107,239			(122,943		)	—			—			18,117			3,186			95,470
Derivative contracts	216			—			(975		)	—			—			975			424			640
Total financial instruments and other inventory positions owned:	96,535			134,401			(146,269		)	266			—			20,559			5,041			110,533
Investments	19,864			14,000			—			—			(266		)	—			31			33,629
Total assets	$	116,399		$	148,401		$	(146,269	)	$	266		$	(266	)	$	20,559		$	5,072		$	144,162
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	7,079		$	(9,438	)	$	54		$	—		$	—		$	9,384		$	5,159		$	12,238
Total financial instruments and other inventory positions sold, but not yet purchased:	$	7,079		$	(9,438	)	$	54		$	—		$	—		$	9,384		$	5,159		$	12,238
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
The following tables summarize the changes in fair value associated with Level III financial instruments during the nine months ended September 30, 2013 and 2012:
	Balance at															Realized			Unrealized			Balance at
	December 31,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2012			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2013
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Fixed income securities	$	—		$	100		$	—		$	—		$	—		$	—		$	—		$	100
Municipal securities:
Tax-exempt securities	1,429			1			—			—			—			(266		)	269			1,433
Short-term securities	656			—			—			—			—			—			—			656
Asset-backed securities	116,171			448,175			(424,274		)	—			—			20,562			(3,592		)	157,042
Derivative contracts	827			710			(13,318		)	—			—			12,523			7,329			8,071
Total financial instruments and other inventory positions owned:	119,083			448,986			(437,592		)	—			—			32,819			4,006			167,302
Investments	33,245			15,363			(10,356		)	—			(619		)	5,946			2,000			45,579
Total assets	$	152,328		$	464,349		$	(447,948	)	$	—		$	(619	)	$	38,765		$	6,006		$	212,881
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	5,218		$	(5,873	)	$	745		$	—		$	—		$	5,115		$	1,376		$	6,581
Total financial instruments and other inventory positions sold, but not yet purchased:	$	5,218		$	(5,873	)	$	745		$	—		$	—		$	5,115		$	1,376		$	6,581
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
	Balance at															Realized			Unrealized			Balance at
	December 31,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2011			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2012
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Convertible securities	$	—		$	30,272		$	(23,400	)	$	2,960		$	—		$	2,010		$	619		$	12,461
Fixed income securities	2,815			38,433			(37,149		)	226			(4,263		)	49			(111		)	—
Municipal securities:
Tax-exempt securities	3,135			1,570			(2,997		)	266			—			(1,156		)	708			1,526
Short-term securities	175			3,075			(1,755		)	—			—			(945		)	(114		)	436
Asset-backed securities	53,088			279,014			(262,383		)	—			—			19,713			6,038			95,470
Derivative contracts	—			—			(3,264		)	—			—			3,264			640			640
Total financial instruments and other inventory positions owned:	59,213			352,364			(330,948		)	3,452			(4,263		)	22,935			7,780			110,533
Investments	21,341			14,000			(3		)	—			(266		)	3			(1,446		)	33,629
Total assets	$	80,554		$	366,364		$	(330,951	)	$	3,452		$	(4,529	)	$	22,938		$	6,334		$	144,162
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Convertible securities	$	1,171		$	—		$	—		$	—		$	(1,171	)	$	—		$	—		$	—
Fixed income securities	900			(897		)	—			—			—			(49		)	46			—
Derivative contracts	3,594			(18,858		)	1,434			—			—			17,424			8,644			12,238
Total financial instruments and other inventory positions sold, but not yet purchased:	$	5,665		$	(19,755	)	$	1,434		$	—		$	(1,171	)	$	17,375		$	8,690		$	12,238
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
The carrying values of some of the Company’s financial instruments approximate fair value due to their liquid or short-term nature. Such financial assets and financial liabilities include cash, securities either purchased or sold under agreements to resell, receivables and payables either from or to customers and brokers, dealers and clearing organizations and short-term financings.

Variable_Interest_Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2013
Variable Interest Entities Disclosure [Abstract]	'
Variable Interest Entities	'
	Variable Interest Entities
	In the normal course of business, the Company periodically creates or transacts with entities that are investment vehicles organized as partnerships or limited liability companies. These entities were established for the purpose of investing in securities of public or private companies, or municipal debt obligations and were initially financed through the capital commitments of the members. The Company has investments in and/or acts as the managing partner of these entities. In certain instances, the Company provides management and investment advisory services for which it earns fees generally based upon the market value of assets under management and may include incentive fees based upon performance. The Company’s aggregate investments in these investment vehicles totaled $109.5 million and $96.9 million at September 30, 2013 and December 31, 2012, respectively, and are recorded in other assets on the consolidated statements of financial condition. The Company’s remaining capital commitments to these entities was $35.9 million at September 30, 2013.
	Variable interest entities (“VIEs”) are entities in which equity investors lack the characteristics of a controlling financial interest or do not have sufficient equity at risk for the entity to finance its activities. The determination as to whether an entity is a VIE is based on the amount and nature of the members’ equity investment in the entity. The Company also considers other characteristics such as the power through voting rights or similar rights to direct the activities of an entity that most significantly impact the entity’s economic performance. For those entities that meet the deferral provisions defined by FASB ASU No. 2010-10, "Consolidation: Amendments for Certain Investment Funds," ("ASU 2010-10"), the Company considers characteristics such as the ability to influence the decision making about the entity’s activities and how the entity is financed. The Company has identified certain of the entities described above as VIEs. These VIEs had net assets approximating $0.7 billion and $0.8 billion at September 30, 2013 and December 31, 2012, respectively. The Company’s exposure to loss from these VIEs is $6.4 million, which is the carrying value of its capital contributions recorded in other assets on the consolidated statements of financial condition at September 30, 2013. The Company had no liabilities related to these VIEs at September 30, 2013 and December 31, 2012.
	The Company is required to consolidate all VIEs for which it is considered to be the primary beneficiary. The determination as to whether the Company is considered to be the primary beneficiary is based on whether the Company has both the power to direct the activities of the VIE that most significantly impact the entity’s economic performance and the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. For those entities that meet the deferral provisions defined by ASU 2010-10, the determination as to whether the Company is considered to be the primary beneficiary differs in that it is based on whether the Company will absorb a majority of the VIE’s expected losses, receive a majority of the VIE’s expected residual returns, or both. The Company determined it is not the primary beneficiary of these VIEs and accordingly does not consolidate them. Furthermore, the Company has not provided financial or other support to these VIEs that it was not previously contractually required to provide as of September 30, 2013.

Receivables_from_and_Payables_

Receivables from and Payables to Brokers, Dealers and Clearing Organizations	9 Months Ended
	Sep. 30, 2013
Brokers and Dealers [Abstract]	'
Receivables from and Payables to Brokers, Dealers and Clearing Organizations	'
	Receivables from and Payables to Brokers, Dealers and Clearing Organizations
	Amounts receivable from brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Receivable arising from unsettled securities transactions	$	112,613	$	66,426
	Deposits paid for securities borrowed	36,395		32,163
	Receivable from clearing organizations	22,025		17,655
	Deposits with clearing organizations	47,799		24,717
	Securities failed to deliver	9,222		5,440
	Other	14,249		1,716
		$	242,303	$	148,117
	Amounts payable to brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Payable arising from unsettled securities transactions	$	96,097	$	24,643
	Payable to clearing organizations	14,265		5,763
	Securities failed to receive	7,919		7,459
	Other	8,071		22,290
		$	126,352	$	60,155
	Deposits paid for securities borrowed approximate the market value of the securities. Securities failed to deliver and receive represent the contract value of securities that have not been delivered or received by the Company on settlement date.

Collateralized_Securities_Tran

Collateralized Securities Transactions

9 Months Ended

Sep. 30, 2013

Collateralized Securities Transactions Disclosure [Abstract]

'

Collateralized Securities Transactions

'

Collateralized Securities Transactions

The Company’s financing and customer securities activities involve the Company using securities as collateral. In the event that the counterparty does not meet its contractual obligation to return securities used as collateral (e.g., pursuant to the terms of a repurchase agreement), or customers do not deposit additional securities or cash for margin when required, the Company may be exposed to the risk of reacquiring the securities or selling the securities at unfavorable market prices in order to satisfy its obligations to its customers or counterparties. The Company seeks to control this risk by monitoring the market value of securities pledged or used as collateral on a daily basis and requiring adjustments in the event of excess market exposure. The Company also uses unaffiliated third party custodians to administer the underlying collateral for certain of its repurchase agreements and short-term financing to mitigate risk.

A reverse repurchase agreement is a transaction in which the Company purchases financial instruments from a seller, typically in exchange for cash, and simultaneously enters into an agreement to resell the same or substantially the same financial instruments to the seller at a stated price plus accrued interest at a future date. A repurchase agreement is a transaction in which the Company sells financial instruments to a buyer, typically in exchange for cash, and simultaneously enters into an agreement to repurchase the same or substantially the same financial instruments from the buyer at a stated price plus accrued interest at a future date. Even though repurchase and reverse repurchase agreements involve the legal transfer of ownership of financial instruments, they are accounted for as financing arrangements because they require the financial instruments to be repurchased or resold at maturity of the agreement.

In a securities borrowed transaction, the Company borrows securities from a counterparty in exchange for cash. When the Company returns the securities, the counterparty returns the cash. Interest is generally paid periodically over the life of the transaction.

In the normal course of business, the Company obtains securities purchased under agreements to resell, securities borrowed and margin agreements on terms that permit it to repledge or resell the securities to others, typically pursuant to repurchase agreements. The Company obtained securities with a fair value of approximately $268.0 million and $186.1 million at September 30, 2013 and December 31, 2012, respectively, of which $258.0 million and $174.4 million, respectively, had been pledged or otherwise transferred to satisfy its commitments under financial instruments and other inventory positions sold, but not yet purchased.

The following is a summary of the Company’s securities sold under agreements to repurchase ("Repurchase Liabilities"), the fair market value of related collateral pledged and the interest rate charged by the Company’s counterparty, which is based on LIBOR plus an applicable margin, as of September 30, 2013:

Repurchase

Fair Market

(Dollars in thousands)

Liabilities

Value

Interest Rate

Term up to 30 day maturities:

Asset-backed securities

$

4,062

$

5,625

1.68%

On demand maturities:

U.S. government agency securities

74,852

78,383

0.3 - 0.55%

$

78,914

$

84,008

Reverse repurchase agreements, repurchase agreements and securities borrowed and loaned are reported on a net basis by counterparty when a legal right of offset exists. The following table provides information about the offsetting of these instruments and related collateral amounts at September 30, 2013:

Gross Amount

Net Amounts

Gross Amounts Not Offset

Offset on the

Presented on the

on the Consolidated Statements

Gross

Consolidated

Consolidated

of Financial Condition

(Dollars in thousands)

Recognized

Statements of

Statements of

Financial

Collateral

Net

Description

Assets

Financial Condition

Financial Condition

Instruments

Received (1)

Amount

Reverse repurchase agreements

$

227,423

$

(41,999

)

$

185,424

$

—

$

(185,424

)

$

—

Securities borrowed (3)

36,395

—

36,395

—

(36,395

)

—

Gross Amount

Net Amount

Gross Amount Not Offset

Offset on the

Presented on the

on the Consolidated Statements

Gross

Consolidated

Consolidated

of Financial Condition

(Dollars in thousands)

Recognized

Statements of

Statements of

Financial

Collateral

Net

Description

Liabilities

Financial Condition

Financial Condition

Instruments

Pledged (2)

Amount

Repurchase agreements

$

78,914

$

(41,999

)

$

36,915

$

—

$

(36,915

)

$

—

-1

Includes securities received by the Company from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default.

-2

Includes the fair value of securities pledged by the Company to the counterparty. These securities are included on the consolidated statements of financial condition unless the Company defaults.

-3

Deposits paid for securities borrowed are included in receivables from brokers, dealers and clearing organizations on the consolidated statements of financial condition. See Note 9 for additional information on receivables from brokers, dealers and clearing organizations.

There were no gross amounts offset on the consolidated statements of financial condition for reverse repurchase agreements, securities borrowed or repurchase agreements at December 31, 2012 as a legal right of offset did not exist. The Company had no outstanding securities lending arrangements as of September 30, 2013 or December 31, 2012. See Note 6 for information related to the Company's offsetting of derivative contracts.

Other_Assets

Other Assets	9 Months Ended
	Sep. 30, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Other Assets	'
	Other Assets
	Other assets include net deferred income tax assets, proprietary investments, income tax receivables and prepaid expenses. The Company’s investments include investments in private companies and partnerships, registered mutual funds, warrants of public and private companies and private company debt. Other assets included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Net deferred income tax assets	$	27,689	$	33,622
	Investments at fair value	59,572		39,055
	Investments at cost	25,303		26,364
	Investments accounted for under the equity method	20,273		20,353
	Income tax receivables	5,656		5,448
	Prepaid expenses	3,253		3,840
	Other	1,672		1,015
	Total other assets	$	143,418	$	129,697
	Management regularly reviews the Company’s investments in private company debt and has concluded that no valuation allowance is needed as it is probable that all contractual principal and interest will be collected.
	At September 30, 2013, investments carried on a cost basis had an estimated fair market value of $44.7 million. The estimated fair value of these investments was measured using discounted cash flow models that utilize market data for comparable companies (e.g., multiples of revenue and earnings before interest, taxes, depreciation and amortization ("EBITDA")). Because valuation adjustments, based upon management’s judgment, were made to account for differences between the measured security and comparable securities, investments carried at cost would be categorized as Level III assets in the fair value hierarchy, if they were carried at fair value.
	Investments accounted for under the equity method include general and limited partnership interests. The carrying value of these investments is based on the investment vehicle’s net asset value. The net assets of investment partnerships consist of investments in both marketable and non-marketable securities. The underlying investments held by such partnerships are valued based on the estimated fair value ultimately determined by management in our capacity as general partner or investor and, in the case of investments in unaffiliated investment partnerships, are based on financial statements prepared by the unaffiliated general partners.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	Goodwill and Intangible Assets
	The following table presents the changes in the carrying value of goodwill and intangible assets from continuing operations for the nine months ended September 30, 2013:
		Capital			Asset
	(Dollars in thousands)	Markets			Management			Total
	Goodwill
	Balance at December 31, 2012	$	—		$	196,844		$	196,844
	Goodwill acquired	13,956			—			13,956
	Impairment charge	—			—			—
	Balance at September 30, 2013	$	13,956		$	196,844		$	210,800
	Intangible assets
	Balance at December 31, 2012	$	—		$	41,258		$	41,258
	Intangible assets acquired	6,924			—			6,924
	Amortization of intangible assets	(1,238		)	(4,983		)	(6,221		)
	Balance at September 30, 2013	$	5,686		$	36,275		$	41,961
	The addition of goodwill and intangible assets during the nine months ended September 30, 2013 related to the acquisitions of Seattle-Northwest and Edgeview, as discussed in Note 4. Management identified $6.9 million of intangible assets, consisting of customer relationships ($6.2 million) and non-competition agreements ($0.7 million), which will be amortized over a weighted average life of 1.7 years and 3.0 years, respectively.
	The following table summarizes the future aggregate amortization of the Company's intangible assets with determinable lives:
	(Dollars in thousands)
	Remainder of 2013	$	3,147
	2014	8,200
	2015	7,050
	2016	6,219
	2017	5,230
	Thereafter	9,255
	Total	$	39,101

ShortTerm_Financing

Short-Term Financing	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Short-Term Financing	'
	Short-Term Financing
	The following is a summary of short-term financing and the weighted average interest rate on borrowings:
		Outstanding Balance				Weighted Average Interest Rate
		September 30,		December 31,		September 30,	December 31,
	(Dollars in thousands)	2013		2012		2013	2012
	Commercial paper (secured)	$	345,733	$	304,439	1.47%	1.65%
	Prime broker arrangement	223,556		172,575		0.92%	0.98%
	Bank lines (secured)	94,000		—		1.50%	N/A
	Total short-term financing	$	663,289	$	477,014
	The Company issues secured commercial paper to fund a portion of its securities inventory. The secured commercial paper notes (“CP Notes”) can be issued with maturities of 27 days to 270 days from the date of issuance. The CP Notes are issued under three separate programs, CP Series A, CP Series II A and CP Series III A, and are secured by different inventory classes. As of September 30, 2013, the weighted average maturity of CP Series A, CP Series II A and CP Series III A was 128 days, 108 days and 32 days, respectively. The CP Notes are interest bearing or sold at a discount to par with an interest rate based on LIBOR plus an applicable margin.
	The Company has established an arrangement to obtain financing with a prime broker related to its municipal bond funds. Financing under this arrangement is secured by certain securities, primarily municipal securities, and collateral limitations could reduce the amount of funding available under this arrangement. The funding is at the discretion of the prime broker.
	The Company has committed short-term bank line financing available on a secured basis and uncommitted short-term bank line financing available on both a secured and unsecured basis. The Company uses these credit facilities in the ordinary course of business to fund a portion of its daily operations and the amount borrowed under these credit facilities varies daily based on the Company’s funding needs.
	The Company’s committed short-term bank line financing at September 30, 2013 consisted of a one-year $250 million committed revolving credit facility with U.S. Bank, N.A., which was renewed in December 2012. Advances under this facility are secured by certain marketable securities. The facility includes a covenant that requires the Company’s U.S. broker dealer subsidiary to maintain a minimum net capital of $120 million, and the unpaid principal amount of all advances under this facility will be due on December 28, 2013. The Company pays a nonrefundable commitment fee on the unused portion of the facility on a quarterly basis. At September 30, 2013, the Company had no advances against this line of credit.
	The Company’s uncommitted secured lines at September 30, 2013 totaled $185 million with two banks and are dependent on having appropriate collateral, as determined by the bank agreement, to secure an advance under the line. The availability of the Company’s uncommitted lines are subject to approval by the individual banks each time an advance is requested and may be denied. At September 30, 2013, the Company had $94.0 million in advances against these lines of credit.

Variable_Rate_Senior_Notes

Variable Rate Senior Notes	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Variable Rate Senior Notes	'
	Variable Rate Senior Notes
	On November 30, 2012, the Company entered into a note purchase agreement (“Note Purchase Agreement”) under which the Company issued unsecured variable rate senior notes (“Notes”) in the amount of $125 million. The initial holders of the Notes are certain entities advised by PIMCO. The Notes consist of two classes, Class A Notes and Class B Notes, with principal amounts of $50 million and $75 million, respectively. The Class A Notes bear interest at a rate equal to three-month LIBOR plus 4.00 percent and mature on May 31, 2014. The Class B Notes bear interest at a rate equal to three-month LIBOR plus 4.50 percent and mature on November 30, 2015. Interest on the Notes is adjustable and payable quarterly. The unpaid principal amounts are due in full on the respective maturity dates and are not subject to prepayment at the Company's discretion. The proceeds from the Notes were used to repay the outstanding balance under the bank syndicated credit agreement (“Credit Agreement”) discussed in Note 15. The remaining proceeds are being used for general corporate purposes.
	The Note Purchase Agreement includes customary events of default, including failure to pay principal when due or failure to pay interest within five business days of when due, any representation or warranty in the Note Purchase Agreement proving untrue in any material respect when made by the Company, failure to comply with the covenants in the Note Purchase Agreement, failure to pay or another event of default under other material indebtedness in an amount exceeding $10 million, bankruptcy or insolvency of the Company or any of its subsidiaries or a change in control of the Company. If there is any event of default under the Note Purchase Agreement, the noteholders may declare the entire principal and any accrued interest on the Notes to be due and payable and exercise other customary remedies.
	The Note Purchase Agreement includes covenants that, among other things, require the Company to maintain a minimum consolidated tangible net worth and regulatory net capital, limit the Company's leverage ratio and require the Company to maintain a minimum ratio of operating cash flow to fixed charges. With respect to the net capital covenant, the Company's U.S. broker dealer subsidiary is required to maintain minimum net capital of $120 million. At September 30, 2013, the Company was in compliance with all covenants.
	The Notes are recorded at amortized cost. As of September 30, 2013, the carrying value of the Notes approximates fair value.

Bank_Syndicated_Financing

Bank Syndicated Financing	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Bank Syndicated Financing	'
	Bank Syndicated Financing
	On December 29, 2010, the Company entered into a three-year Credit Agreement comprised of a $100 million amortizing term loan and a $50 million revolving credit facility. SunTrust Bank was the administrative agent (“Agent”) for the lenders. The interest rate for borrowing under the Credit Agreement was, at the option of the Company, equal to LIBOR or a base rate, plus an applicable margin, adjustable and payable quarterly at a minimum. The base rate was defined as the highest of the Agent’s prime lending rate, the Federal Funds Rate plus 0.50 percent or one-month LIBOR plus 1.00 percent. The applicable margin varied from 1.50 percent to 3.00 percent and was based on the Company’s leverage ratio. In addition, the Company also paid a nonrefundable commitment fee of 0.50 percent on the unused portion of the revolving credit facility on a quarterly basis. The outstanding balance and unpaid interest on the Credit Agreement was repaid on November 30, 2012 from the proceeds of the Notes discussed in Note 14.

Legal_Contingencies

Legal Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Legal Contingencies	'
	Legal Contingencies
	The Company has been named as a defendant in various legal actions, including complaints and litigation and arbitration claims, arising from its business activities. Such actions include claims related to securities brokerage and investment banking activities, and certain class actions that primarily allege violations of securities laws and seek unspecified damages, which could be substantial. Also, the Company is involved from time to time in investigations and proceedings by governmental agencies and self-regulatory organizations (“SROs”) which could result in adverse judgments, settlement, penalties, fines or other relief.
	The Company has established reserves for potential losses that are probable and reasonably estimable that may result from pending and potential legal actions, investigations and regulatory proceedings. In many cases, however, it is inherently difficult to determine whether any loss is probable or even possible or to estimate the amount or range of any potential loss, particularly where proceedings may be in relatively early stages or where plaintiffs are seeking substantial or indeterminate damages. Matters frequently need to be more developed before a loss or range of loss can reasonably be estimated.
	Given uncertainties regarding the timing, scope, volume and outcome of pending and potential legal actions, investigations and regulatory proceedings and other factors, the amounts of reserves and ranges of reasonably possible losses are difficult to determine and of necessity subject to future revision. Subject to the foregoing and except for the legal proceeding described below, as to which management believes a material loss is reasonably possible, management of the Company believes, based on currently available information, after consultation with outside legal counsel and taking into account its established reserves, that pending legal actions, investigations and regulatory proceedings will be resolved with no material adverse effect on the consolidated statements of financial condition, results of operations or cash flows of the Company. However, if during any period a potential adverse contingency should become probable or resolved for an amount in excess of the established reserves, the results of operations and cash flows in that period and the financial condition as of the end of that period could be materially adversely affected. In addition, there can be no assurance that material losses will not be incurred from claims that have not yet been brought to the Company’s attention or are not yet determined to be reasonably possible.
	The Company has a contingency as to which management of the Company believes that a material loss is reasonably possible. The U.S. Department of Justice Antitrust Division, the SEC and various state attorneys general are conducting broad investigations of numerous firms, including the Company, for possible antitrust and securities violations in connection with the bidding or sale of guaranteed investment contracts and derivatives to municipal issuers from the early 1990s to date. These investigations commenced in November 2006. In addition, several class action complaints were brought on behalf of a proposed class of government entities that purchased municipal derivatives. The complaints, which have been consolidated into a single class action, allege antitrust violations and are pending in the U.S. District Court for the Southern District of New York under the multi-district litigation rules. Several California municipalities also brought separate class action complaints in California federal court, and approximately 18 California municipalities and two New York municipalities filed individual lawsuits that are not part of class actions, all of which have been transferred to the Southern District of New York and consolidated for pretrial purposes. No loss contingency has been reflected in the Company’s consolidated financial statements as this contingency is neither probable nor reasonably estimable at this time. Management is currently unable to estimate a range of reasonably possible loss for these matters because alleged damages have not been specified, the proceedings remain in the early stages, there is uncertainty as to the likelihood of a class or classes being certified or the ultimate size of any class if certified, and there are significant factual issues to be resolved.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2013
Restructuring and Related Activities [Abstract]	'
Restructuring	'
	Restructuring
	For the nine months ended September 30, 2013, the Company incurred pre-tax restructuring charges of $2.9 million from continuing operations. The charge resulted from severance benefits of $2.1 million, $0.5 million for vacating redundant leased office space and $0.3 million for contract termination costs. For the nine months ended September 30, 2012, the Company incurred pre-tax restructuring-related charges of $3.6 million from continuing operations. The charge resulted from severance benefits of $2.4 million and from the reduction of leased office space of $1.2 million.

Shareholders_Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Shareholders' Equity	'
	Shareholders’ Equity
	Share Repurchases
	In the third quarter of 2012, the Company’s board of directors authorized the repurchase of up to $100.0 million in common shares through September 30, 2014. This share repurchase authorization became effective on October 1, 2012. During the nine months ended September 30, 2013, the Company repurchased 1,683,094 shares, or 11.1 percent of the Company’s outstanding common stock at an average price of $32.53 per share for an aggregate purchase price of $54.7 million related to this authorization. The Company has $40.7 million remaining under this authorization. The Company also purchases shares of common stock from restricted stock award recipients upon the award vesting as recipients sell shares to meet their employment tax obligations. The Company purchased 377,479 shares or $15.2 million of the Company’s common stock for this purpose during the nine months ended September 30, 2013.
	Issuance of Shares
	During the nine months ended September 30, 2013, the Company issued 96,049 common shares out of treasury stock in fulfillment of $3.9 million in obligations under the Piper Jaffray Companies Retirement Plan (the “Retirement Plan”) and issued 770,189 common shares out of treasury stock as a result of employee restricted share vesting. During the nine months ended September 30, 2012, the Company issued 165,241 common shares out of treasury stock in fulfillment of $3.8 million in obligations under the Retirement Plan and issued 797,296 common shares out of treasury stock as a result of employee restricted share vesting.

Noncontrolling_Interests

Noncontrolling Interests	9 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Noncontrolling Interests	'
	Noncontrolling Interests
	The consolidated financial statements include the accounts of Piper Jaffray Companies, its wholly owned subsidiaries and other entities in which the Company has a controlling financial interest. Noncontrolling interests represent equity interests in consolidated entities that are not attributable, either directly or indirectly, to Piper Jaffray Companies. Noncontrolling interests include the minority equity holders’ proportionate share of the equity in a municipal bond fund of $128.9 million, a merchant banking fund of $13.3 million and private equity investment vehicles aggregating $7.4 million as of September 30, 2013. As of December 31, 2012, noncontrolling interests included the minority equity holders’ proportionate share of the equity in a municipal bond fund of $43.7 million, a merchant banking fund of $6.4 million and private equity investment vehicles aggregating $6.8 million.
	Ownership interests in entities held by parties other than the Company’s common shareholders are presented as noncontrolling interests within shareholders’ equity, separate from the Company’s own equity. Revenues, expenses and net income or loss are reported on the consolidated statements of operations on a consolidated basis, which includes amounts attributable to both the Company’s common shareholders and noncontrolling interests. Net income or loss is then allocated between the Company and noncontrolling interests based upon their relative ownership interests. Net income applicable to noncontrolling interests is deducted from consolidated net income to determine net income applicable to the Company.
		Common					Total
		Shareholders’			Noncontrolling		Shareholders’
	(Dollars in thousands)	Equity			Interests		Equity
	Balance at December 31, 2012	$	733,292		$	56,883	$	790,175
	Net income	17,956			1,554		19,510
	Amortization/issuance of restricted stock	22,049			—		22,049
	Repurchase of common stock through share repurchase program	(54,743		)	—		(54,743		)
	Repurchase of common stock for employee tax withholding	(15,204		)	—		(15,204		)
	Issuance of treasury shares for 401k match	3,939			—		3,939
	Shares reserved to meet deferred compensation obligations	60			—		60
	Other comprehensive income	16			—		16
	Fund capital contributions, net	—			91,192		91,192
	Balance at September 30, 2013	$	707,365		$	149,629	$	856,994

Compensation_Plans

Compensation Plans	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Compensation Plans	'
	Compensation Plans
	Stock-Based Compensation Plans
	The Company maintains two stock-based compensation plans, the Piper Jaffray Companies Amended and Restated 2003 Annual and Long-Term Incentive Plan (the “Incentive Plan”) and the 2010 Employment Inducement Award Plan (the “Inducement Plan”). The Company’s equity awards are recognized on the consolidated statements of operations at grant date fair value over the service period of the award, net of estimated forfeitures.
	The following table provides a summary of the Company’s outstanding equity awards (in shares or units) as of September 30, 2013:
	Incentive Plan
	Restricted Stock
	Annual grants	879,123
	Sign-on grants	431,624
	Retention grants	—
	Performance grants	—
		1,310,747
	Inducement Plan
	Restricted Stock	58,310
	Total restricted stock related to compensation	1,369,057
	ARI deal consideration (1)	220,456
	Total restricted stock outstanding	1,589,513
	Incentive Plan
	Restricted Stock Units
	Leadership grants	290,536
	Incentive Plan
	Stock options outstanding	470,065
	-1	The Company issued restricted stock as part of deal consideration in conjunction with the acquisition of ARI.
	Incentive Plan
	The Incentive Plan permits the grant of equity awards, including restricted stock, restricted stock units and non-qualified stock options, to the Company’s employees and directors for up to 7.0 million shares of common stock (1.1 million shares remained available for future issuance under the Incentive Plan as of September 30, 2013). The Company believes that such awards help align the interests of employees and directors with those of shareholders and serve as an employee retention tool. The Incentive Plan provides for accelerated vesting of awards if there is a severance event, a change in control of the Company (as defined in the Incentive Plan), in the event of a participant’s death, and at the discretion of the compensation committee of the Company’s board of directors.
	Restricted Stock Awards
	Restricted stock grants are valued at the market price of the Company’s common stock on the date of grant and are amortized over the related requisite service period. The Company grants shares of restricted stock to current employees as part of year-end compensation (“Annual Grants”) and as a retention tool. Employees may receive restricted stock upon initial hiring or as a retention award (“Sign-on Grants”). The Company has also granted incremental restricted stock awards with service conditions to key employees (“Retention Grants”) and restricted stock with performance conditions to members of senior management ("Performance Grants").
	The Company’s Annual Grants are made each year in February. Prior to 2011, Annual Grants had three-year cliff vesting periods. Beginning in 2011, Annual Grants vest ratably over three years in equal installments. The Annual Grants provide for continued vesting after termination of employment, so long as the employee does not violate certain post-termination restrictions set forth in the award agreement or any agreements entered into upon termination. The Company determined the service inception date precedes the grant date for the Annual Grants, and that the post-termination restrictions do not meet the criteria for an in-substance service condition, as defined by FASB Accounting Standards Codification Topic 718, "Compensation – Stock Compensation" ("ASC 718"). Accordingly, restricted stock granted as part of the Annual Grants is expensed in the one-year period in which those awards are deemed to be earned, which is generally the calendar year preceding the February grant date. For example, the Company recognized compensation expense during fiscal 2012 for its February 2013 Annual Grant. If an equity award related to the Annual Grants is forfeited as a result of violating the post-termination restrictions, the lower of the fair value of the award at grant date or the fair value of the award at the date of forfeiture is recorded within the consolidated statements of operations as a reversal of compensation expense. The Company recorded $0.1 million and $0.2 million of forfeitures through compensation and benefits expense within continuing operations for the three months ended September 30, 2013 and 2012, and $0.8 million and $1.3 million for the nine months ended September 30, 2013 and 2012, respectively.
	Sign-on Grants are used as a recruiting tool for new employees and are issued to current employees as a retention tool. These awards have both cliff and ratable vesting terms, and the employees must fulfill service requirements in exchange for rights to the awards. Compensation expense is amortized on a straight-line basis from the grant date over the requisite service period, generally two to five years. Employees forfeit unvested shares upon termination of employment and a reversal of compensation expense is recorded.
	Retention Grants were subject to ratable vesting based upon a five-year service requirement and were amortized as compensation expense on a straight-line basis from the 2008 grant date over the requisite service period, which ended in May 2013. Employees forfeited unvested retention shares upon termination of employment and a reversal of compensation expense was recorded.
	Performance Grants awarded in 2008 and 2009 expired unvested in May 2013.
	Annually, the Company grants stock to its non-employee directors. The stock-based compensation paid to non-employee directors is fully expensed on the grant date and included within outside services expense on the consolidated statements of operations.
	Restricted Stock Units
	The Company granted restricted stock units to its leadership team (“Leadership Grants”) in May 2012 and 2013, respectively. The units will vest and convert to shares of common stock at the end of each 36-month performance period only if the Company satisfies predetermined market conditions over the performance period. Under the terms of the grants, the number of units that will vest and convert to shares will be based on the Company achieving specified market conditions during each performance period as described below. Compensation expense is amortized on a straight-line basis over the three-year requisite service period based on the fair value of the award on the grant date. The market condition must be met for the awards to vest and compensation cost will be recognized regardless if the market condition is satisfied. Employees forfeit unvested share units upon termination of employment with a corresponding reversal of compensation expense.
	Up to 50 percent of the award can be earned based on the Company’s total shareholder return relative to members of a predetermined peer group and up to 50 percent of the award can be earned based on the Company’s total shareholder return. The fair value of the awards on the grant date were determined using a Monte Carlo simulation with the following assumptions:
			Risk-free	Expected Stock
	Grant Year		Interest Rate	Price Volatility
	2013		0.40%	44.00%
	2012		0.38%	47.60%
	Because a portion of the award vesting depends on the Company’s total shareholder return relative to a peer group, the valuation modeled the performance of the peer group as well as the correlation between the Company and the peer group. The expected stock price volatility assumptions were determined using historical volatility as correlation coefficients can only be developed through historical volatility. The risk-free interest rates were determined based on three-year U.S. Treasury bond yields.
	Stock Options
	The Company previously granted options to purchase Piper Jaffray Companies common stock to employees and non-employee directors in fiscal years 2004 through 2008. Employee and director options were expensed by the Company on a straight-line basis over the required service period, based on the estimated fair value of the award on the date of grant using a Black-Scholes option-pricing model. As described above pertaining to the Company’s Annual Grants of restricted shares, stock options granted to employees were expensed in the calendar year preceding the annual February grant date. For example, the Company recognized compensation expense during fiscal 2007 for its February 2008 option grant. The maximum term of the stock options granted to employees and directors is ten years. The Company has not granted stock options since 2008.
	Inducement Plan
	In 2010, the Company established the Inducement Plan in conjunction with the acquisition of ARI. The Company granted $7.0 million in restricted stock (158,801 shares) under the Inducement Plan to ARI employees upon closing of the transaction. These shares vest ratably over five years in equal annual installments ending on March 1, 2015. Inducement Plan awards are amortized as compensation expense on a straight-line basis over the vesting period. Employees forfeit unvested Inducement Plan shares upon termination of employment and a reversal of compensation expense is recorded.
	Stock-Based Compensation Activity
	The Company recorded total compensation expense within continuing operations of $6.1 million and $9.1 million for the three months ended September 30, 2013 and 2012, respectively, and $11.2 million and $15.4 million for the nine months ended September 30, 2013 and 2012, respectively, related to employee restricted stock and restricted stock unit awards. Total compensation cost includes year-end compensation for Annual Grants and the amortization of Sign-on, Retention and Leadership Grants, less forfeitures. The tax benefit related to stock-based compensation costs totaled $2.4 million and $3.5 million for the three months ended September 30, 2013 and 2012, respectively, and $4.4 million and $6.0 million for the nine months ended September 30, 2013 and 2012, respectively.
	The following table summarizes the changes in the Company’s unvested restricted stock (including the unvested restricted stock issued as part of the deal consideration for ARI) under the Incentive Plan and Inducement Plan for the nine months ended September 30, 2013:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2012	2,322,438		$	37.01
	Granted	656,934		38.45
	Vested	(1,140,292	)	39.99
	Canceled	(249,567	)	38.46
	September 30, 2013	1,589,513		$	31.1
	The following summarizes the changes in the Company’s unvested restricted stock units under the Incentive Plan for the nine months ended September 30, 2013:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2012	173,271		$	12.12
	Granted	117,265		21.32
	Vested	—		—
	Canceled	—		—
	September 30, 2013	290,536		$	15.83
As of September 30, 2013, there was $14.6 million of total unrecognized compensation cost related to restricted stock and restricted stock units expected to be recognized over a weighted average period of 2.94 years.
The following table summarizes the changes in the Company’s outstanding stock options for the nine months ended September 30, 2013:
					Weighted Average
			Weighted		Remaining
	Options		Average		Contractual Term	Aggregate
	Outstanding		Exercise Price		(in Years)	Intrinsic Value
31-Dec-12	486,563		$	44.76	2.9	$	94,150
Granted	—		—
Exercised	—		—
Canceled	(16,498	)	42.91
September 30, 2013	470,065		$	44.82	2.2	$	147,071
Options exercisable at September 30, 2013	470,065		$	44.82	2.2	$	147,071
As of September 30, 2013, there was no unrecognized compensation cost related to stock options expected to be recognized over future years.
The fair value of options exercised, cash received from option exercises and the resulting tax benefit realized for the tax deductions from option exercises were immaterial for the nine months ended September 30, 2013 and 2012, respectively.
Deferred Compensation Plan
In 2012, the Company established the Piper Jaffray Companies Mutual Fund Restricted Share Investment Plan, a deferred compensation plan which allows eligible employees to elect to receive a portion of the incentive compensation they would otherwise receive in the form of restricted stock or other equity, instead in MFRS Awards of registered funds managed by the Company's asset management business. MFRS Awards are awarded to qualifying employees in February of each year, and represent a portion of their compensation for performance in the preceding year similar to the Company's Annual Grants. MFRS Awards vest ratably over three years in equal installments and provide for continued vesting after termination of employment so long as the employee does not violate certain post-termination restrictions set forth in the award agreement or any agreement entered into upon termination. Forfeitures are recorded as a reduction of compensation and benefits expense within the consolidated statements of operations.
The Company has also granted MFRS Awards to new employees as a recruiting tool. Employees must fulfill service requirements in exchange for rights to the awards. Compensation expense from these awards will be amortized on a straight-line basis over the requisite service period of two to five years.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	The Company calculates earnings per share using the two-class method. Basic earnings per common share is computed by dividing net income applicable to Piper Jaffray Companies’ common shareholders by the weighted average number of common shares outstanding for the period. Net income applicable to Piper Jaffray Companies’ common shareholders represents net income applicable to Piper Jaffray Companies reduced by the allocation of earnings to participating securities. Losses are not allocated to participating securities. All of the Company’s unvested restricted shares are deemed to be participating securities as they are eligible to share in the profits (e.g., receive dividends) of the Company. The Company’s unvested restricted stock units are not participating securities as they are not eligible to share in the profits of the Company. Diluted earnings per common share is calculated by adjusting the weighted average outstanding shares to assume conversion of all potentially dilutive stock options.
	The computation of earnings per share is as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Amounts in thousands, except per share data)	2013			2012			2013			2012
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,851		$	14,493		$	21,877		$	31,510
	Net income/(loss) from discontinued operations	(1,529		)	5,171			(3,921		)	(2,066		)
	Net income applicable to Piper Jaffray Companies	5,322			19,664			17,956			29,444
	Earnings allocated to participating securities (1)	(496		)	(2,824		)	(1,793		)	(4,293		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	4,826		$	16,840		$	16,163		$	25,151
	Shares for basic and diluted calculations:
	Average shares used in basic computation	14,621			15,210			15,271			15,736
	Stock options	5			—			13			—
	Average shares used in diluted computation	14,626			15,210			15,284			15,736
	Earnings/(loss) per basic common share:
	Income from continuing operations	$	0.42		$	0.82		$	1.29		$	1.71
	Income/(loss) from discontinued operations	(0.09		)	0.29			(0.23		)	(0.11		)
	Earnings per basic common share	$	0.33		$	1.11		$	1.06		$	1.6
	Earnings/(loss) per diluted common share:
	Income from continuing operations	$	0.42		$	0.82		$	1.29		$	1.71
	Income/(loss) from discontinued operations	(0.09		)	0.29			(0.23		)	(0.11		)
	Earnings per diluted common share	$	0.33		$	1.11		$	1.06		$	1.6
	-1	Represents the allocation of earnings to participating securities. Losses are not allocated to participating securities. Participating securities include all of the Company’s unvested restricted shares. The weighted average participating shares outstanding were 1,504,665 and 2,550,888 for the three months ended September 30, 2013 and 2012, respectively, and 1,695,130 and 2,686,255 for the nine months ended September 30, 2013 and 2012, respectively.
	-2	Net income applicable to Piper Jaffray Companies’ common shareholders for diluted and basic EPS may differ under the two-class method as a result of adding the effect of the assumed exercise of stock options to dilutive shares outstanding, which alters the ratio used to allocate earnings to Piper Jaffray Companies’ common shareholders and participating securities for purposes of calculating diluted and basic EPS.
	The anti-dilutive effects from stock options were immaterial for the nine months ended September 30, 2013 and 2012.

Segment_Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segment Reporting	'
	Segment Reporting
	Basis for Presentation
	The Company structures its segments primarily based upon the nature of the financial products and services provided to customers and the Company’s management organization. The Company evaluates performance and allocates resources based on segment pre-tax operating income or loss and segment pre-tax operating margin. Revenues and expenses directly associated with each respective segment are included in determining their operating results. Other revenues and expenses that are not directly attributable to a particular segment are allocated based upon the Company’s allocation methodologies, including each segment’s respective net revenues, use of shared resources, headcount or other relevant measures. The financial management of assets is performed on an enterprise-wide basis. As such, assets are not assigned to the business segments.
	Segment pre-tax operating income and segment pre-tax operating margin exclude the results of discontinued operations.
	Reportable segment financial results from continuing operations are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Capital Markets
	Investment banking
	Financing
	Equities	$	30,010		$	18,781		$	66,085		$	55,141
	Debt	12,808			16,573			51,971			53,598
	Advisory services	20,215			16,317			39,180			41,670
	Total investment banking	63,033			51,671			157,236			150,409
	Institutional sales and trading
	Equities	22,960			17,927			65,087			55,589
	Fixed income	20,437			46,690			53,439			95,773
	Total institutional sales and trading	43,397			64,617			118,526			151,362
	Other income/(loss)	3,833			(1,039		)	7,519			(2,141		)
	Net revenues	110,263			115,249			283,281			299,630
	Operating expenses (1)	103,906			94,671			266,301			266,529
	Segment pre-tax operating income	$	6,357		$	20,578		$	16,980		$	33,101
	Segment pre-tax operating margin	5.8		%	17.9		%	6		%	11		%
	Asset Management
	Management and performance fees
	Management fees	$	17,547		$	15,800		$	52,212		$	47,213
	Performance fees	60			22			716			664
	Total management and performance fees	17,607			15,822			52,928			47,877
	Other income	444			434			1,410			534
	Net revenues	18,051			16,256			54,338			48,411
	Operating expenses (1)	12,348			11,482			37,757			35,283
	Segment pre-tax operating income	$	5,703		$	4,774		$	16,581		$	13,128
	Segment pre-tax operating margin	31.6		%	29.4		%	30.5		%	27.1		%
	Total
	Net revenues	$	128,314		$	131,505		$	337,619		$	348,041
	Operating expenses (1)	116,254			106,153			304,058			301,812
	Pre-tax operating income	$	12,060		$	25,352		$	33,561		$	46,229
	Pre-tax operating margin	9.4		%	19.3		%	9.9		%	13.3		%
	-1	Operating expenses include intangible asset amortization expense as set forth in the table below:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Capital Markets	$	1,238		$	—		$	1,238		$	—
	Asset Management	1,661			1,736			4,983			5,208
	Total intangible asset amortization expense	$	2,899		$	1,736		$	6,221		$	5,208
	Geographic Areas
	The Company operates in both U.S. and non-U.S. markets. The Company’s non-U.S. business activities are principally conducted through European locations. Net revenues and long-lived assets for the Company's Asian locations were not significant. Net revenues disclosed in the following table reflect the regional view, with financing revenues allocated to geographic locations based upon the location of the capital market, advisory revenues allocated based upon the location of the investment banking team and net institutional sales and trading revenues allocated based upon the location of the client. Asset management revenues are allocated to the U.S. based upon the geographic location of the Company’s asset management team. Net revenues exclude discontinued operations for all periods presented.
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues:
	United States	$	126,458		$	128,580		$	329,379		$	339,727
	Europe	1,856			2,925			8,240			8,314
	Consolidated	$	128,314		$	131,505		$	337,619		$	348,041
	Long-lived assets are allocated to geographic locations based upon the location of the asset. The following table presents long-lived assets held for use by geographic region:
		September 30,			December 31,
	(Dollars in thousands)	2013			2012
	Long-lived assets:
	United States	$	294,936		$	285,682
	Europe	793			1,131
	Consolidated	$	295,729		$	286,813

Net_Capital_Requirements_and_O

Net Capital Requirements and Other Regulatory Matters	9 Months Ended
	Sep. 30, 2013
Banking and Thrift [Abstract]	'
Net Capital Requirements and Other Regulatory Matters	'
	Net Capital Requirements and Other Regulatory Matters
	Piper Jaffray is registered as a securities broker dealer with the SEC and is a member of various SROs and securities exchanges. The Financial Industry Regulatory Authority (“FINRA”) serves as Piper Jaffray’s primary SRO. Piper Jaffray is subject to the uniform net capital rule of the SEC and the net capital rule of FINRA. Piper Jaffray has elected to use the alternative method permitted by the SEC rule, which requires that it maintain minimum net capital of the greater of $1.0 million or 2 percent of aggregate debit balances arising from customer transactions, as such term is defined in the SEC rule. Under its rules, FINRA may prohibit a member firm from expanding its business or paying dividends if resulting net capital would be less than 5 percent of aggregate debit balances. Advances to affiliates, repayment of subordinated debt, dividend payments and other equity withdrawals by Piper Jaffray are subject to certain notification and other provisions of SEC and FINRA rules. In addition, Piper Jaffray is subject to certain notification requirements related to withdrawals of excess net capital.
	At September 30, 2013, net capital calculated under the SEC rule was $150.2 million, and exceeded the minimum net capital required under the SEC rule by $149.2 million.
	The Company’s short-term committed credit facility of $250 million and its variable rate senior notes include covenants requiring Piper Jaffray to maintain minimum net capital of $120 million.
	Piper Jaffray Ltd., our broker dealer subsidiary registered in the United Kingdom, was subject to the capital requirements of the Prudential Regulation Authority and the Financial Conduct Authority. As of September 30, 2013, Piper Jaffray Ltd. was in compliance with the capital requirements of the Prudential Regulation Authority and the Financial Conduct Authority.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company's effective income tax rate from continuing operations, excluding noncontrolling interests, for the three months ended September 30, 2013 was 29.6 percent, compared to 41.3 percent for the three months ended September 30, 2012. The effective income tax rate for the three months ended September 30, 2013 was unusually low due to the impact of tax-exempt interest income representing a larger proportion of pre-tax income from continuing operations.
	For the nine months ended September 30, 2013, the Company’s effective income tax rate from continuing operations, excluding noncontrolling interests, was 31.6 percent, compared to 27.7 percent for the nine months ended September 30, 2012. The provision for income taxes for the nine months ended September 30, 2012 was low compared to pre-tax income from continuing operations due to the reversal of a previously accrued uncertain state income tax position of $7.1 million, net of federal income tax, related to the completion of a state tax audit examination in the second quarter of 2012. This reversal was offset in part by accrued income tax expense on operating profits generated from the Company's U.S. entities and a $4.0 million write-off of deferred tax assets related to equity grants that were forfeited or vested at share prices lower than the grant date share prices.
	The Company's income tax benefit from discontinued operations was $1.0 million and $22.0 million for the three months ended September 30, 2013 and 2012, respectively. For the nine months ended September 30, 2013 and 2012, the income tax benefit was $1.2 million and $21.7 million, respectively. The Company's income tax benefit from discontinued operations in the third quarter of 2012 is primarily due to U.S. tax deductions for the Company's realized losses on investments in its Hong Kong subsidiaries. The tax benefit was the excess of the tax basis of the Company's investment in the subsidiaries over the financial statement carrying amount (the deductible outside basis difference).

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	The following table summarizes the estimated fair values of assets acquired and liabilities assumed at the respective dates of acquisition:
	(Dollars in thousands)
	Assets
	Cash and cash equivalents		$	8,014
	Financial instruments and other inventory positions owned		24,074
	Fixed assets		1,247
	Goodwill		13,956
	Intangible assets		6,924
	Other receivables		2,280
	Other assets		6,642
	Total assets acquired		63,137
	Liabilities
	Payables		1,126
	Financial instruments and other inventory positions sold, but not yet purchased		22,588
	Accrued compensation		1,469
	Other liabilities and accrued expenses		5,214
	Total liabilities assumed		30,397
	Net assets acquired		$	32,740
Business Acquisition, Pro Forma Information	'
	The consolidated Company's unaudited pro forma information presented does not necessarily reflect the results of operations that would have resulted had the acquisitions been completed at the beginning of the applicable periods presented, does not contemplate anticipated operational efficiencies of the combined entities, nor does it indicate the results of operations in future periods.
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
	(Dollars in thousands)	2013			2012		2013		2012
	Net revenues	$	132,773		$	139,877	$	353,728	$	374,646
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,948		$	14,187	$	20,631	$	30,930

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2013
Hong Kong Capital Markets	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement	'
	The components of discontinued operations for the Hong Kong capital markets business are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues	$	—		$	2,674		$	—		$	6,625
	Restructuring expenses	—			11,057			—			11,057
	Other expenses	158			5,843			517			16,550
	Total non-interest expenses	158			16,900			517			27,607
	Loss from discontinued operations before income tax benefit	(158		)	(14,226		)	(517		)	(20,982		)
	Income tax benefit	(61		)	(21,029		)	(151		)	(20,969		)
	Income/(loss) from discontinued operations, net of tax	$	(97	)	$	6,803		$	(366	)	$	(13	)
FAMCO	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement	'
	The components of discontinued operations for FAMCO are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues	$	—		$	1,453		$	1,716		$	4,228
	Total non-interest expenses	2,365			4,090			4,486			6,962
	Loss from discontinued operations before income tax benefit	(2,365		)	(2,637		)	(2,770		)	(2,734		)
	Income tax benefit	(933		)	(1,005		)	(1,091		)	(681		)
	Loss from discontinued operations	(1,432		)	(1,632		)	(1,679		)	(2,053		)
	Loss on sale, net of tax	—			—			(1,876		)	—
	Loss from discontinued operations, net of tax	$	(1,432	)	$	(1,632	)	$	(3,555	)	$	(2,053	)

Financial_Instruments_and_Othe1

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure Financial Instruments And Other Inventory Positions Owned And Financial Instruments And Other Inventory Positions Sold But Not Yet Purchased [Abstract]	'
Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but not yet Purchased	'
	Financial instruments and other inventory positions owned and financial instruments and other inventory positions sold, but not yet purchased were as follows:
		September 30,				December 31,
	(Dollars in thousands)	2013				2012
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	28,203			$	16,478
	Convertible securities	73,216				44,978
	Fixed income securities	22,106				33,668
	Municipal securities:
	Taxable securities	250,608				164,059
	Tax-exempt securities	560,403				418,189
	Short-term securities	99,522				68,328
	Asset-backed securities	157,059				116,195
	U.S. government agency securities	303,359				304,259
	U.S. government securities	233				4,966
	Derivative contracts	38,629				40,475
	Total financial instruments and other inventory positions owned	1,533,338				1,211,595
	Less noncontrolling interests (1)	(276,379		)		(103,480		)
		$	1,256,959			$	1,108,115
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	58,599			$	27,090
	Convertible securities	198				1,015
	Fixed income securities	17,022				19,314
	Municipal securities:
	Short-term securities	—				60
	U.S. government agency securities	79,135				73,724
	U.S. government securities	353,321				231,043
	Derivative contracts	5,473				4,955
	Total financial instruments and other inventory positions sold, but not yet purchased	513,748				357,201
	Less noncontrolling interests (2)	(66,047		)		(27,308		)
		$	447,701			$	329,893
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $104.1 million and $43.8 million of taxable municipal securities, $168.2 million and $58.0 million of tax-exempt municipal securities, and $4.1 million and $1.7 million of derivative contracts as of September 30, 2013 and December 31, 2012, respectively.
	-2	Noncontrolling interests attributable to third party ownership interests in a consolidated municipal bond fund consist of $66.0 million and $27.3 million of U.S. government securities as of September 30, 2013 and December 31, 2012, respectively.
Total Absolute Notional Contract Amount	'
	The following table presents the total absolute notional contract amount associated with the Company’s outstanding derivative instruments:
	(Dollars in thousands)				September 30,				December 31,
	Transaction Type or Hedged Security		Derivative Category		2013				2012
	Customer matched-book		Interest rate derivative contract		$	5,345,918			$	5,569,096
	Trading securities		Interest rate derivative contract		270,500				244,250
	Trading securities		Credit default swap index contract		494,233				230,650
					$	6,110,651			$	6,043,996
Unrealized Gains/(Losses) on Derivative Instruments	'
	The following table presents the Company’s unrealized gains/(losses) on derivative instruments:
					Three Months Ended								Nine Months Ended
	(Dollars in thousands)				September 30,								September 30,
	Derivative Category		Operations Category		2013				2012				2013			2012
	Interest rate derivative contract		Investment banking		$	(483	)		$	(440	)		$	(1,132	)	$	(2,045	)
	Interest rate derivative contract		Institutional brokerage		(16,532		)		(4,735		)		4,930			(8,003		)
	Credit default swap index contract		Institutional brokerage		(1,918		)		(1,782		)		(650		)	(1,422		)
					$	(18,933	)		$	(6,957	)		$	3,148		$	(11,470	)
Gross Fair Market Value of Derivative Instruments and Location on Consolidated Statements of Financial Condition Prior to Counterparty and Cash Collateral Netting by Asset or Liability Position	'
	The gross fair market value of all derivative instruments and their location on the Company’s consolidated statements of financial condition prior to counterparty netting are shown below by asset or liability position (1):
	(Dollars in thousands)				Asset Value at						Liability Value at
					September 30,						September 30,
	Derivative Category		Financial Condition Location		2013				Financial Condition Location		2013
	Interest rate derivative contract		Financial instruments and other inventory positions owned		$	402,823			Financial instruments and other inventory positions sold,  but not yet purchased		$	375,806
	Credit default swap index contract		Financial instruments and other inventory positions owned		11,187				Financial instruments and other inventory positions sold,  but not yet purchased		7,185
					$	414,010					$	382,991
	-1	Amounts are disclosed at gross fair value in accordance with the requirements of FASB Accounting Standards Codification Topic 815, "Derivatives and Hedging" ("ASC 815").

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Information about Significant Unobservable Inputs used in Fair Value Measurement	'
	The following table summarizes quantitative information about the significant unobservable inputs used in the fair value measurement of the Company’s Level III financial instruments as of September 30, 2013:
		Valuation					Weighted
		Technique		Unobservable Input	Range		Average
	Assets:
	Financial instruments and other inventory positions owned:
	Municipal securities:
	Tax-exempt securities	Discounted cash flow		Debt service coverage ratio (2)	5 - 69%		22.20%
	Short-term securities	Discounted cash flow		Expected recovery rate  (% of par) (2)	77 - 80%		79.60%
	Asset-backed securities:
	Collateralized by residential mortgages	Discounted cash flow		Credit default rates (3)	1 - 9%		5.40%
				Prepayment rates (4)	1 - 9%		4.90%
				Loss severity (3)	45 - 100%		66.90%
				Valuation yields (3)	5 - 7%		5.80%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	5 - 30 bps		11.4 bps
	Investments:
	Warrants in private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 35%		30.20%
				Stock volatility factors of comparable companies (2)	39 - 127%		52.20%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 3 times		2.8 times
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	12 - 31 bps		23.2 bps
	Sensitivity of the fair value to changes in unobservable inputs:
	-1	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly lower/(higher) fair value measurement.
	-2	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly higher/(lower) fair value measurement.
	-3	Significant changes in any of these inputs in isolation could result in a significantly different fair value. Generally, a change in the assumption used for credit default rates is accompanied by a directionally similar change in the assumption used for the loss severity and a directionally inverse change in the assumption for valuation yields.
	-4	The potential impact of changes in prepayment rates on fair value is dependent on other security-specific factors, such as the par value and structure. Changes in the prepayment rates may result in directionally similar or directionally inverse changes in fair value depending on whether the security trades at a premium or discount to the par value.
Valuation of Financial Instruments by Pricing Observability Levels	'
	The following table summarizes the valuation of the Company’s financial instruments by pricing observability levels defined in FASB Accounting Standards Codification Topic 820, "Fair Value Measurement" ("ASC 820") as of September 30, 2013:
											Counterparty
											and Cash
											Collateral
	(Dollars in thousands)	Level I			Level II			Level III			Netting (1)			Total
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	25,289		$	2,914		$	—		$	—		$	28,203
	Convertible securities	—			73,216			—			—			73,216
	Fixed income securities	—			22,006			100			—			22,106
	Municipal securities:
	Taxable securities	—			250,608			—			—			250,608
	Tax-exempt securities	—			558,970			1,433			—			560,403
	Short-term securities	—			98,866			656			—			99,522
	Asset-backed securities	—			17			157,042			—			157,059
	U.S. government agency securities	—			303,359			—			—			303,359
	U.S. government securities	233			—			—			—			233
	Derivative contracts	—			405,939			8,071			(375,381		)	38,629
	Total financial instruments and other inventory positions owned:	25,522			1,715,895			167,302			(375,381		)	1,533,338
	Cash equivalents	1,670			—			—			—			1,670
	Investments	13,417			576			45,579			—			59,572
	Total assets	$	40,609		$	1,716,471		$	212,881		$	(375,381	)	$	1,594,580
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	56,928		$	1,671		$	—		$	—		$	58,599
	Convertible securities	—			198			—			—			198
	Fixed income securities	—			17,022			—			—			17,022
	U.S. government agency securities	—			79,135			—			—			79,135
	U.S. government securities	353,321			—			—			—			353,321
	Derivative contracts	—			376,410			6,581			(377,518		)	5,473
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	410,249		$	474,436		$	6,581		$	(377,518	)	$	513,748
	-1	Represents cash collateral and the impact of netting on a counterparty basis. The Company had no securities posted as collateral to its counterparties.
	The following table summarizes the valuation of the Company’s financial instruments by pricing observability levels defined in ASC 820 as of December 31, 2012:
											Counterparty
											and Cash
											Collateral
	(Dollars in thousands)	Level I			Level II			Level III			Netting (1)			Total
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	3,180		$	13,298		$	—		$	—		$	16,478
	Convertible securities	—			44,978			—			—			44,978
	Fixed income securities	—			33,668			—			—			33,668
	Municipal securities:
	Taxable securities	—			164,059			—			—			164,059
	Tax-exempt securities	—			416,760			1,429			—			418,189
	Short-term securities	—			67,672			656			—			68,328
	Asset-backed securities	—			24			116,171			—			116,195
	U.S. government agency securities	—			304,259			—			—			304,259
	U.S. government securities	4,966			—			—			—			4,966
	Derivative contracts	—			595,486			827			(555,838		)	40,475
	Total financial instruments and other inventory positions owned:	8,146			1,640,204			119,083			(555,838		)	1,211,595
	Cash equivalents	51,346			—			—			—			51,346
	Investments	5,810			—			33,245			—			39,055
	Total assets	$	65,302		$	1,640,204		$	152,328		$	(555,838	)	$	1,301,996
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	25,362		$	1,728		$	—		$	—		$	27,090
	Convertible securities	—			1,015			—			—			1,015
	Fixed income securities	—			19,314			—			—			19,314
Municipal securities:
Short-term securities	—			60			—			—			60
U.S. government agency securities	—			73,724			—			—			73,724
U.S. government securities	231,043			—			—			—			231,043
Derivative contracts	—			569,764			5,218			(570,027		)	4,955
Total financial instruments and other inventory positions sold, but not yet purchased:	$	256,405		$	665,605		$	5,218		$	(570,027	)	$	357,201
-1	Represents cash collateral and the impact of netting on a counterparty basis. The Company had no securities posted as collateral to its counterparties.
Changes in Fair Value Associated with Level III Financial Instruments	'
	The following tables summarize the changes in fair value associated with Level III financial instruments during the nine months ended September 30, 2013 and 2012:
		Balance at															Realized			Unrealized			Balance at
		December 31,									Transfers			Transfers			gains/			gains/			September 30,
	(Dollars in thousands)	2012			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2013
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Fixed income securities	$	—		$	100		$	—		$	—		$	—		$	—		$	—		$	100
	Municipal securities:
	Tax-exempt securities	1,429			1			—			—			—			(266		)	269			1,433
	Short-term securities	656			—			—			—			—			—			—			656
	Asset-backed securities	116,171			448,175			(424,274		)	—			—			20,562			(3,592		)	157,042
	Derivative contracts	827			710			(13,318		)	—			—			12,523			7,329			8,071
	Total financial instruments and other inventory positions owned:	119,083			448,986			(437,592		)	—			—			32,819			4,006			167,302
	Investments	33,245			15,363			(10,356		)	—			(619		)	5,946			2,000			45,579
	Total assets	$	152,328		$	464,349		$	(447,948	)	$	—		$	(619	)	$	38,765		$	6,006		$	212,881
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts	$	5,218		$	(5,873	)	$	745		$	—		$	—		$	5,115		$	1,376		$	6,581
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	5,218		$	(5,873	)	$	745		$	—		$	—		$	5,115		$	1,376		$	6,581
	-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
		Balance at															Realized			Unrealized			Balance at
		December 31,									Transfers			Transfers			gains/			gains/			September 30,
	(Dollars in thousands)	2011			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2012
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Convertible securities	$	—		$	30,272		$	(23,400	)	$	2,960		$	—		$	2,010		$	619		$	12,461
	Fixed income securities	2,815			38,433			(37,149		)	226			(4,263		)	49			(111		)	—
	Municipal securities:
	Tax-exempt securities	3,135			1,570			(2,997		)	266			—			(1,156		)	708			1,526
	Short-term securities	175			3,075			(1,755		)	—			—			(945		)	(114		)	436
	Asset-backed securities	53,088			279,014			(262,383		)	—			—			19,713			6,038			95,470
	Derivative contracts	—			—			(3,264		)	—			—			3,264			640			640
	Total financial instruments and other inventory positions owned:	59,213			352,364			(330,948		)	3,452			(4,263		)	22,935			7,780			110,533
	Investments	21,341			14,000			(3		)	—			(266		)	3			(1,446		)	33,629
	Total assets	$	80,554		$	366,364		$	(330,951	)	$	3,452		$	(4,529	)	$	22,938		$	6,334		$	144,162
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Convertible securities	$	1,171		$	—		$	—		$	—		$	(1,171	)	$	—		$	—		$	—
	Fixed income securities	900			(897		)	—			—			—			(49		)	46			—
	Derivative contracts	3,594			(18,858		)	1,434			—			—			17,424			8,644			12,238
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	5,665		$	(19,755	)	$	1,434		$	—		$	(1,171	)	$	17,375		$	8,690		$	12,238
	-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations
	The following tables summarize the changes in fair value associated with Level III financial instruments during the three months ended September 30, 2013 and 2012:
		Balance at															Realized			Unrealized			Balance at
		June 30,									Transfers			Transfers			gains/			gains/			September 30,
	(Dollars in thousands)	2013			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2013
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Convertible securities	$	1,308		$	—		$	(1,615	)	$	—		$	(251	)	$	839		$	(281	)	$	—
	Fixed income securities	100			—			—			—			—			—			—			100
	Municipal securities:
	Tax-exempt securities	1,433			—			—			—			—			—			—			1,433
	Short-term securities	656			—			—			—			—			—			—			656
	Asset-backed securities	151,396			99,763			(97,246		)	—			—			(276		)	3,405			157,042
	Derivative contracts	17,879			—			(12,337		)	—			—			12,337			(9,808		)	8,071
	Total financial instruments and other inventory positions owned:	172,772			99,763			(111,198		)	—			(251		)	12,900			(6,684		)	167,302
	Investments	53,567			—			(10,356		)	—			(619		)	5,942			(2,955		)	45,579
	Total assets	$	226,339		$	99,763		$	(121,554	)	$	—		$	(870	)	$	18,842		$	(9,639	)	$	212,881
	Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	254		$	(223	)	$	—		$	—		$	—		$	223		$	6,327		$	6,581
Total financial instruments and other inventory positions sold, but not yet purchased:	$	254		$	(223	)	$	—		$	—		$	—		$	223		$	6,327		$	6,581
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.
	Balance at															Realized			Unrealized			Balance at
	June 30,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2012			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2012
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Convertible securities	$	3,681		$	27,142		$	(21,249	)	$	—		$	—		$	2,051		$	836		$	12,461
Municipal securities:
Tax-exempt securities	2,373			20			(1,102		)	266			—			(584		)	553			1,526
Short-term securities	394			—			—			—			—			—			42			436
Asset-backed securities	89,871			107,239			(122,943		)	—			—			18,117			3,186			95,470
Derivative contracts	216			—			(975		)	—			—			975			424			640
Total financial instruments and other inventory positions owned:	96,535			134,401			(146,269		)	266			—			20,559			5,041			110,533
Investments	19,864			14,000			—			—			(266		)	—			31			33,629
Total assets	$	116,399		$	148,401		$	(146,269	)	$	266		$	(266	)	$	20,559		$	5,072		$	144,162
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	7,079		$	(9,438	)	$	54		$	—		$	—		$	9,384		$	5,159		$	12,238
Total financial instruments and other inventory positions sold, but not yet purchased:	$	7,079		$	(9,438	)	$	54		$	—		$	—		$	9,384		$	5,159		$	12,238
-1	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations.

Receivables_from_and_Payables_1

Receivables from and Payables to Brokers, Dealers and Clearing Organizations (Tables)	9 Months Ended
	Sep. 30, 2013
Brokers and Dealers [Abstract]	'
Brokers, Dealers and Clearing Organizations	'
	Amounts receivable from brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Receivable arising from unsettled securities transactions	$	112,613	$	66,426
	Deposits paid for securities borrowed	36,395		32,163
	Receivable from clearing organizations	22,025		17,655
	Deposits with clearing organizations	47,799		24,717
	Securities failed to deliver	9,222		5,440
	Other	14,249		1,716
		$	242,303	$	148,117
	Amounts payable to brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Payable arising from unsettled securities transactions	$	96,097	$	24,643
	Payable to clearing organizations	14,265		5,763
	Securities failed to receive	7,919		7,459
	Other	8,071		22,290
		$	126,352	$	60,155

Collateralized_Securities_Tran1

Collateralized Securities Transactions (Tables)	9 Months Ended
	Sep. 30, 2013
Collateralized Securities Transactions Disclosure [Abstract]	'
Summary of Repurchase Liabilities, Fair Market Value of Related Collateral Pledged and Interest Rate Charged	'
	The following is a summary of the Company’s securities sold under agreements to repurchase ("Repurchase Liabilities"), the fair market value of related collateral pledged and the interest rate charged by the Company’s counterparty, which is based on LIBOR plus an applicable margin, as of September 30, 2013:
		Repurchase			Fair Market
	(Dollars in thousands)	Liabilities			Value				Interest Rate
	Term up to 30 day maturities:
	Asset-backed securities	$	4,062		$	5,625			1.68%
	On demand maturities:
	U.S. government agency securities	74,852			78,383				0.3 - 0.55%
		$	78,914		$	84,008
Offsetting Assets and Liabilities	'
	The following table provides information about the offsetting of these instruments and related collateral amounts at September 30, 2013:
						Gross Amount				Net Amounts		Gross Amounts Not Offset
						Offset on the				Presented on the		on the Consolidated Statements
			Gross			Consolidated				Consolidated		of Financial Condition
	(Dollars in thousands)		Recognized			Statements of				Statements of		Financial		Collateral			Net
	Description		Assets			Financial Condition				Financial Condition		Instruments		Received (1)			Amount
	Reverse repurchase agreements		$	227,423		$	(41,999	)		$	185,424	$	—	$	(185,424	)	$	—
	Securities borrowed (3)		36,395			—				36,395		—		(36,395		)	—
						Gross Amount				Net Amount		Gross Amount Not Offset
						Offset on the				Presented on the		on the Consolidated Statements
			Gross			Consolidated				Consolidated		of Financial Condition
	(Dollars in thousands)		Recognized			Statements of				Statements of		Financial		Collateral			Net
	Description		Liabilities			Financial Condition				Financial Condition		Instruments		Pledged (2)			Amount
	Repurchase agreements		$	78,914		$	(41,999	)		$	36,915	$	—	$	(36,915	)	$	—
	-1	Includes securities received by the Company from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default.
	-2	Includes the fair value of securities pledged by the Company to the counterparty. These securities are included on the consolidated statements of financial condition unless the Company defaults.
	-3	Deposits paid for securities borrowed are included in receivables from brokers, dealers and clearing organizations on the consolidated statements of financial condition. See Note 9 for additional information on receivables from brokers, dealers and clearing organizations.

Other_Assets_Tables

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Other Assets	'
	Other assets include net deferred income tax assets, proprietary investments, income tax receivables and prepaid expenses. The Company’s investments include investments in private companies and partnerships, registered mutual funds, warrants of public and private companies and private company debt. Other assets included:
		September 30,		December 31,
	(Dollars in thousands)	2013		2012
	Net deferred income tax assets	$	27,689	$	33,622
	Investments at fair value	59,572		39,055
	Investments at cost	25,303		26,364
	Investments accounted for under the equity method	20,273		20,353
	Income tax receivables	5,656		5,448
	Prepaid expenses	3,253		3,840
	Other	1,672		1,015
	Total other assets	$	143,418	$	129,697

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Carrying Value of Goodwill and Intangible Assets	'
	The following table presents the changes in the carrying value of goodwill and intangible assets from continuing operations for the nine months ended September 30, 2013:
		Capital			Asset
	(Dollars in thousands)	Markets			Management			Total
	Goodwill
	Balance at December 31, 2012	$	—		$	196,844		$	196,844
	Goodwill acquired	13,956			—			13,956
	Impairment charge	—			—			—
	Balance at September 30, 2013	$	13,956		$	196,844		$	210,800
	Intangible assets
	Balance at December 31, 2012	$	—		$	41,258		$	41,258
	Intangible assets acquired	6,924			—			6,924
	Amortization of intangible assets	(1,238		)	(4,983		)	(6,221		)
	Balance at September 30, 2013	$	5,686		$	36,275		$	41,961
Schedule of Expected Amortization Expense [Table Text Block]	'
	The following table summarizes the future aggregate amortization of the Company's intangible assets with determinable lives:
	(Dollars in thousands)
	Remainder of 2013	$	3,147
	2014	8,200
	2015	7,050
	2016	6,219
	2017	5,230
	Thereafter	9,255
	Total	$	39,101

ShortTerm_Financing_Tables

Short-Term Financing (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Summary of Short-Term Financing and Weighted Average Interest Rate on Borrowings	'
	The following is a summary of short-term financing and the weighted average interest rate on borrowings:
		Outstanding Balance				Weighted Average Interest Rate
		September 30,		December 31,		September 30,	December 31,
	(Dollars in thousands)	2013		2012		2013	2012
	Commercial paper (secured)	$	345,733	$	304,439	1.47%	1.65%
	Prime broker arrangement	223,556		172,575		0.92%	0.98%
	Bank lines (secured)	94,000		—		1.50%	N/A
	Total short-term financing	$	663,289	$	477,014

Noncontrolling_Interests_Table

Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Changes in Common Shareholders' Equity Attributable to Parent Company and Equity Attributable to Noncontrolling Interests	'
		Common					Total
		Shareholders’			Noncontrolling		Shareholders’
	(Dollars in thousands)	Equity			Interests		Equity
	Balance at December 31, 2012	$	733,292		$	56,883	$	790,175
	Net income	17,956			1,554		19,510
	Amortization/issuance of restricted stock	22,049			—		22,049
	Repurchase of common stock through share repurchase program	(54,743		)	—		(54,743		)
	Repurchase of common stock for employee tax withholding	(15,204		)	—		(15,204		)
	Issuance of treasury shares for 401k match	3,939			—		3,939
	Shares reserved to meet deferred compensation obligations	60			—		60
	Other comprehensive income	16			—		16
	Fund capital contributions, net	—			91,192		91,192
	Balance at September 30, 2013	$	707,365		$	149,629	$	856,994

Compensation_Plans_Tables

Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of Outstanding Equity Awards	'
	The following table provides a summary of the Company’s outstanding equity awards (in shares or units) as of September 30, 2013:
	Incentive Plan
	Restricted Stock
	Annual grants	879,123
	Sign-on grants	431,624
	Retention grants	—
	Performance grants	—
		1,310,747
	Inducement Plan
	Restricted Stock	58,310
	Total restricted stock related to compensation	1,369,057
	ARI deal consideration (1)	220,456
	Total restricted stock outstanding	1,589,513
	Incentive Plan
	Restricted Stock Units
	Leadership grants	290,536
	Incentive Plan
	Stock options outstanding	470,065
	-1	The Company issued restricted stock as part of deal consideration in conjunction with the acquisition of ARI.
Schedule of Valuation Assumptions	'
	The fair value of the awards on the grant date were determined using a Monte Carlo simulation with the following assumptions:
			Risk-free	Expected Stock
	Grant Year		Interest Rate	Price Volatility
	2013		0.40%	44.00%
	2012		0.38%	47.60%
Changes in Unvested Restricted Stock	'
	The following table summarizes the changes in the Company’s unvested restricted stock (including the unvested restricted stock issued as part of the deal consideration for ARI) under the Incentive Plan and Inducement Plan for the nine months ended September 30, 2013:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2012	2,322,438		$	37.01
	Granted	656,934		38.45
	Vested	(1,140,292	)	39.99
	Canceled	(249,567	)	38.46
	September 30, 2013	1,589,513		$	31.1
Changes in Unvested Restricted Stock Units	'
	The following summarizes the changes in the Company’s unvested restricted stock units under the Incentive Plan for the nine months ended September 30, 2013:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2012	173,271		$	12.12
	Granted	117,265		21.32
	Vested	—		—
	Canceled	—		—
	September 30, 2013	290,536		$	15.83
Changes in Outstanding Stock Options	'
	The following table summarizes the changes in the Company’s outstanding stock options for the nine months ended September 30, 2013:
						Weighted Average
				Weighted		Remaining
		Options		Average		Contractual Term	Aggregate
		Outstanding		Exercise Price		(in Years)	Intrinsic Value
	31-Dec-12	486,563		$	44.76	2.9	$	94,150
	Granted	—		—
	Exercised	—		—
	Canceled	(16,498	)	42.91
	September 30, 2013	470,065		$	44.82	2.2	$	147,071
	Options exercisable at September 30, 2013	470,065		$	44.82	2.2	$	147,071

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Computation of Earnings per Share	'
	The computation of earnings per share is as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Amounts in thousands, except per share data)	2013			2012			2013			2012
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,851		$	14,493		$	21,877		$	31,510
	Net income/(loss) from discontinued operations	(1,529		)	5,171			(3,921		)	(2,066		)
	Net income applicable to Piper Jaffray Companies	5,322			19,664			17,956			29,444
	Earnings allocated to participating securities (1)	(496		)	(2,824		)	(1,793		)	(4,293		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	4,826		$	16,840		$	16,163		$	25,151
	Shares for basic and diluted calculations:
	Average shares used in basic computation	14,621			15,210			15,271			15,736
	Stock options	5			—			13			—
	Average shares used in diluted computation	14,626			15,210			15,284			15,736
	Earnings/(loss) per basic common share:
	Income from continuing operations	$	0.42		$	0.82		$	1.29		$	1.71
	Income/(loss) from discontinued operations	(0.09		)	0.29			(0.23		)	(0.11		)
	Earnings per basic common share	$	0.33		$	1.11		$	1.06		$	1.6
	Earnings/(loss) per diluted common share:
	Income from continuing operations	$	0.42		$	0.82		$	1.29		$	1.71
	Income/(loss) from discontinued operations	(0.09		)	0.29			(0.23		)	(0.11		)
	Earnings per diluted common share	$	0.33		$	1.11		$	1.06		$	1.6
	-1	Represents the allocation of earnings to participating securities. Losses are not allocated to participating securities. Participating securities include all of the Company’s unvested restricted shares. The weighted average participating shares outstanding were 1,504,665 and 2,550,888 for the three months ended September 30, 2013 and 2012, respectively, and 1,695,130 and 2,686,255 for the nine months ended September 30, 2013 and 2012, respectively.
	-2	Net income applicable to Piper Jaffray Companies’ common shareholders for diluted and basic EPS may differ under the two-class method as a result of adding the effect of the assumed exercise of stock options to dilutive shares outstanding, which alters the ratio used to allocate earnings to Piper Jaffray Companies’ common shareholders and participating securities for purposes of calculating diluted and basic EPS.

Segment_Reporting_Tables

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Reportable Segment Financial Results	'
	Reportable segment financial results from continuing operations are as follows:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Capital Markets
	Investment banking
	Financing
	Equities	$	30,010		$	18,781		$	66,085		$	55,141
	Debt	12,808			16,573			51,971			53,598
	Advisory services	20,215			16,317			39,180			41,670
	Total investment banking	63,033			51,671			157,236			150,409
	Institutional sales and trading
	Equities	22,960			17,927			65,087			55,589
	Fixed income	20,437			46,690			53,439			95,773
	Total institutional sales and trading	43,397			64,617			118,526			151,362
	Other income/(loss)	3,833			(1,039		)	7,519			(2,141		)
	Net revenues	110,263			115,249			283,281			299,630
	Operating expenses (1)	103,906			94,671			266,301			266,529
	Segment pre-tax operating income	$	6,357		$	20,578		$	16,980		$	33,101
	Segment pre-tax operating margin	5.8		%	17.9		%	6		%	11		%
	Asset Management
	Management and performance fees
	Management fees	$	17,547		$	15,800		$	52,212		$	47,213
	Performance fees	60			22			716			664
	Total management and performance fees	17,607			15,822			52,928			47,877
	Other income	444			434			1,410			534
	Net revenues	18,051			16,256			54,338			48,411
	Operating expenses (1)	12,348			11,482			37,757			35,283
	Segment pre-tax operating income	$	5,703		$	4,774		$	16,581		$	13,128
	Segment pre-tax operating margin	31.6		%	29.4		%	30.5		%	27.1		%
	Total
	Net revenues	$	128,314		$	131,505		$	337,619		$	348,041
	Operating expenses (1)	116,254			106,153			304,058			301,812
	Pre-tax operating income	$	12,060		$	25,352		$	33,561		$	46,229
	Pre-tax operating margin	9.4		%	19.3		%	9.9		%	13.3		%
	-1	Operating expenses include intangible asset amortization expense as set forth in the table below:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Capital Markets	$	1,238		$	—		$	1,238		$	—
	Asset Management	1,661			1,736			4,983			5,208
	Total intangible asset amortization expense	$	2,899		$	1,736		$	6,221		$	5,208
Net Revenues by Geographic Locations	'
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2013			2012			2013			2012
	Net revenues:
	United States	$	126,458		$	128,580		$	329,379		$	339,727
	Europe	1,856			2,925			8,240			8,314
	Consolidated	$	128,314		$	131,505		$	337,619		$	348,041
Long-Lived Assets by Geographic Region	'
	The following table presents long-lived assets held for use by geographic region:
		September 30,			December 31,
	(Dollars in thousands)	2013			2012
	Long-lived assets:
	United States	$	294,936		$	285,682
	Europe	793			1,131
	Consolidated	$	295,729		$	286,813

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Number of reportable segments	2

Acquisitions_Additional_Inform

Acquisitions - Additional Information(Details) (USD $)	9 Months Ended				0 Months Ended		0 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Jul. 16, 2013	Sep. 30, 2013	Jul. 16, 2013	Jul. 16, 2013	Jul. 16, 2013
		Capital Markets	Capital Markets	Capital Markets	Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.
			Customer Relationships	Noncompete Agreements			Minimum	Maximum	Weighted Average
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'	'
Consideration transferred	'	'	'	'	$32,700,000	'	'	'	'
Acquisition related compensation arrangements	'	'	'	'	14,300,000	'	'	'	'
Acquisition Related Compensation Arrangement Award Vesting Period	'	'	'	'	'	'	'2 years	'5 years	'4 years 3 months
Goodwill acquired	13,956,000	13,956,000	'	'	'	'	'	'	'
Goodwill amount expected to be deducted for income tax purposes	'	'	'	'	8,900,000	'	'	'	'
Intangible assets	6,924,000	6,924,000	6,200,000	700,000	'	6,924,000	'	'	'
Acquisition related costs	'	'	'	'	$900,000	'	'	'	'

Acquisitions_Estimated_Fair_Va

Acquisitions - Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Assets	'	'
Goodwill	$210,800	$196,844
Intangible assets	6,924	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	'	'
Assets	'	'
Cash and cash equivalents	8,014	'
Financial instruments and other inventory positions owned	24,074	'
Fixed assets	1,247	'
Goodwill	13,956	'
Intangible assets	6,924	'
Other receivables	2,280	'
Other assets	6,642	'
Total assets acquired	63,137	'
Liabilities	'	'
Payables	1,126	'
Financial instruments and other inventory positions sold, but not yet purchased	22,588	'
Accrued compensation	1,469	'
Other liabilities and accrued expenses	5,214	'
Total liabilities assumed	30,397	'
Net assets acquired	$32,740	'

Acquisitions_Unaudited_Pro_For

Acquisitions - Unaudited Pro Forma Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Business Combinations [Abstract]	'	'	'	'
Net revenues	$132,773	$139,877	$353,728	$374,646
Net income from continuing operations applicable to Piper Jaffray Companies	$6,948	$14,187	$20,631	$30,930

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Loss on sale, net of tax	'	'	($1,876)	$0
Loss from discontinued operations, net of tax	-1,529	5,171	-3,921	-2,066
Hong Kong Capital Markets	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Net revenues	0	2,674	0	6,625
RestructureExpenseFromDiscontinuedOperations	0	11,057	0	11,057
DiscontinuedOperationsOperatingExpenseExcludeRestructure	158	5,843	517	16,550
Total non-interest expenses	158	16,900	517	27,607
Loss from discontinued operations before income tax benefit	-158	-14,226	-517	-20,982
Income tax benefit	-61	-21,029	-151	-20,969
Loss from discontinued operations, net of tax	-97	6,803	-366	-13
FAMCO	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Net revenues	0	1,453	1,716	4,228
Total non-interest expenses	2,365	4,090	4,486	6,962
Loss from discontinued operations before income tax benefit	-2,365	-2,637	-2,770	-2,734
Income tax benefit	-933	-1,005	-1,091	-681
Loss from discontinued operations	-1,432	-1,632	-1,679	-2,053
Loss on sale, net of tax	0	0	-1,876	0
Loss from discontinued operations, net of tax	($1,432)	($1,632)	($3,555)	($2,053)

Discontinued_Operations_Detail1

Discontinued Operations (Details Textual) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Loss on sale of FAMCO	'	'	'	($1,876,000)	$0
FAMCO	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Loss on sale of FAMCO	'	0	0	-1,876,000	0
Sale of FAMCO, sale price	4,000,000	'	'	'	'
Sale of FAMCO, cash proceeds	300,000	'	'	'	'
Sale of FAMCO, note receivable received	3,700,000	'	'	'	'
FAMCO | Other Liabilities and Accrued Expenses	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Sale of FAMCO, indemnification accrual	'	$4,700,000	'	$4,700,000	'

Financial_Instruments_and_Othe2

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	$1,533,338	$1,211,595
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-276,379	-103,480
Financial instruments and other inventory positions owned, attributable to parent	1,256,959	1,108,115
Financial instruments and other inventory positions sold, but not yet purchased	513,748	357,201
Financial instruments and other inventory positions owned and pledged as collateral, attributable to noncontrolling interest	-66,047	-27,308
Financial instruments and other inventory positions owned and pledged as collateral, attributable to parent	447,701	329,893
Financial instruments and other inventory positions owned and pledged as collateral	1,118,910	826,806
Equity securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	28,203	16,478
Financial instruments and other inventory positions sold, but not yet purchased	58,599	27,090
Convertible securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	73,216	44,978
Financial instruments and other inventory positions sold, but not yet purchased	198	1,015
Fixed income securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	22,106	33,668
Financial instruments and other inventory positions sold, but not yet purchased	17,022	19,314
Taxable securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	250,608	164,059
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-104,100	-43,800
Tax-exempt securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	560,403	418,189
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-168,200	-58,000
Short-term securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	99,522	68,328
Financial instruments and other inventory positions sold, but not yet purchased	0	60
Asset-backed securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	157,059	116,195
U.S. government agency securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	303,359	304,259
Financial instruments and other inventory positions sold, but not yet purchased	79,135	73,724
U.S. government securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	233	4,966
Financial instruments and other inventory positions sold, but not yet purchased	353,321	231,043
Financial instruments and other inventory positions owned and pledged as collateral, attributable to noncontrolling interest	-66,000	-27,300
Derivative contracts	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	38,629	40,475
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-4,100	-1,700
Financial instruments and other inventory positions sold, but not yet purchased	$5,473	$4,955

Financial_Instruments_and_Othe3

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased - Total Absolute Notional Contract Amount (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	$6,110,651	$6,043,996
Customer matched-book | Interest rate derivative contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	5,345,918	5,569,096
Trading securities | Interest rate derivative contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	270,500	244,250
Trading securities | Credit default swap index contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	$494,233	$230,650

Financial_Instruments_and_Othe4

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased - Unrealized Gains/(Losses) on Derivative Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	($18,933)	($6,957)	$3,148	($11,470)
Interest rate derivative contract | Investment banking	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	-483	-440	-1,132	-2,045
Interest rate derivative contract | Institutional brokerage	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	-16,532	-4,735	4,930	-8,003
Credit default swap index contract | Institutional brokerage	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	($1,918)	($1,782)	($650)	($1,422)

Financial_Instruments_and_Othe5

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased - Gross Fair Market Value of Derivative Instruments (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'
Fair value of derivative assets, gross	$414,010	[1]
Fair value of derivative liabilities, gross	382,991	[1]
Financial instruments and other inventory positions owned | Interest rate derivative contract	'
Derivative [Line Items]	'
Fair value of derivative assets, gross	402,823	[1]
Financial instruments and other inventory positions owned | Credit default swap index contract	'
Derivative [Line Items]	'
Fair value of derivative assets, gross	11,187	[1]
Financial instruments and other inventory positions sold, but not yet purchased | Interest rate derivative contract	'
Derivative [Line Items]	'
Fair value of derivative liabilities, gross	375,806	[1]
Financial instruments and other inventory positions sold, but not yet purchased | Credit default swap index contract	'
Derivative [Line Items]	'
Fair value of derivative liabilities, gross	$7,185	[1]
[1]	Amounts are disclosed at gross fair value in accordance with the requirements of FASB Accounting Standards Codification Topic 815, "Derivatives and Hedging" ("ASC 815").

Financial_Instruments_and_Othe6

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased - Additional Information (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'
Uncollateralized credit exposure	$23.60
Notional contract amount of derivatives with counterparties not required to post collateral	201.7
Counterparty	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'
Uncollateralized credit exposure	$11.10

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Other assets	$143,418,000	'	$143,418,000	'	$129,697,000
Gains from fair value changes	'	'	9,500,000	2,300,000	'
Transfers of financial assets from Level III	870,000	266,000	619,000	4,529,000	'
Level III	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Total assets	212,881,000	'	212,881,000	'	152,328,000
Percentage of Level III assets to financial instruments measured at fair value	13.40%	'	13.40%	'	11.70%
Investments [Member]	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Transfers of financial assets from Level III	900,000	'	600,000	'	'
Merchant Banking Investments	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Other assets	$15,100,000	'	$15,100,000	'	'
U.S. government agency securities | Minimum	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Market yields basis points spreads to treasury securities (as a percent)	1.40%	'	1.40%	'	'
Prepayment expectations based upon PSA prepayment levels	200	'	200	'	'
U.S. government agency securities | Maximum	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Market yields basis points spreads to treasury securities (as a percent)	2.00%	'	2.00%	'	'
Prepayment expectations based upon PSA prepayment levels	350	'	350	'	'

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Information about Significant Unobservable Inputs used in Fair Value Measurement (Details) (Level III)	9 Months Ended
	Sep. 30, 2013
Financial instruments and other inventory positions sold, but not yet purchased | Minimum | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.12%
Financial instruments and other inventory positions sold, but not yet purchased | Maximum | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.31%
Financial instruments and other inventory positions sold, but not yet purchased | Weighted Average | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.23%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Tax-exempt securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Debt service coverage ratio	5.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Short-term securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Expected recovery rate (% of par)	77.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Collateralized by Residential mortgages	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Credit default rate	1.00%
Prepayment rates	1.00%
Loss severity	45.00%
Valuation yields	5.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.05%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Equity investment in private company	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Revenue multiple	2
Financial instruments and other inventory positions owned | Minimum | Black-Scholes option pricing model | Warrants in public and private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Liquidity discount rates	30.00%
Financial instruments and other inventory positions owned | Minimum | Black-Scholes option pricing model | Warrants in private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Stock volatility factors of comparable companies	39.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Tax-exempt securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Debt service coverage ratio	69.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Short-term securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Expected recovery rate (% of par)	80.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Collateralized by Residential mortgages	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Credit default rate	9.00%
Prepayment rates	9.00%
Loss severity	100.00%
Valuation yields	7.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.30%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Equity investment in private company	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Revenue multiple	3
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Warrants in public and private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Liquidity discount rates	35.00%
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Warrants in private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Stock volatility factors of comparable companies	127.00%
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Tax-exempt securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Debt service coverage ratio	22.20%	[1]
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Short-term securities	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Expected recovery rate (% of par)	79.60%	[1]
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Collateralized by Residential mortgages	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Credit default rate	5.40%	[2]
Prepayment rates	4.90%	[3]
Loss severity	66.90%	[2]
Valuation yields	5.80%	[2]
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Interest rate derivative contract	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Unamortized premium over the MMD curve	0.11%
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Equity investment in private company	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Revenue multiple	2.8
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Warrants in public and private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Liquidity discount rates	30.20%	[4]
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Warrants in private companies	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'
Stock volatility factors of comparable companies	52.20%	[1]
[1]	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly higher/(lower) fair value measurement.
[2]	Significant changes in any of these inputs in isolation could result in a significantly different fair value. Generally, a change in the assumption used for credit default rates is accompanied by a directionally similar change in the assumption used for the loss severity and a directionally inverse change in the assumption for valuation yields.
[3]	The potential impact of changes in prepayment rates on fair value is dependent on other security-specific factors, such as the par value and structure. Changes in the prepayment rates may result in directionally similar or directionally inverse changes in fair value depending on whether the security trades at a premium or discount to the par value.
[4]	Significant increase/(decrease) in the unobservable input in isolation would result in a significantly lower/(higher) fair value measurement.

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Valuation of Financial Instruments by Pricing Observability Levels (Details) (USD $)	Sep. 30, 2013		Jun. 30, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	$1,533,338		'	$1,211,595		'	'	'
Investments	59,572		'	39,055		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	513,748		'	357,201		'	'	'
Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	28,203		'	16,478		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	58,599		'	27,090		'	'	'
Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	73,216		'	44,978		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	198		'	1,015		'	'	'
Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	22,106		'	33,668		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	17,022		'	19,314		'	'	'
Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	250,608		'	164,059		'	'	'
Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	560,403		'	418,189		'	'	'
Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	99,522		'	68,328		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	0		'	60		'	'	'
Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	157,059		'	116,195		'	'	'
U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	303,359		'	304,259		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	79,135		'	73,724		'	'	'
U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	233		'	4,966		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	353,321		'	231,043		'	'	'
Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	38,629		'	40,475		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	5,473		'	4,955		'	'	'
Level I	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	25,522		'	8,146		'	'	'
Cash equivalents	1,670		'	51,346		'	'	'
Investments	13,417		'	5,810		'	'	'
Total assets	40,609		'	65,302		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	410,249		'	256,405		'	'	'
Level I | Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	25,289		'	3,180		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	56,928		'	25,362		'	'	'
Level I | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level I | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level I | Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Level I | Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Level I | Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level I | Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Level I | U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level I | U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	233		'	4,966		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	353,321		'	231,043		'	'	'
Level I | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level II	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	1,715,895		'	1,640,204		'	'	'
Cash equivalents	'		'	'		'	'	'
Investments	576		'	'		'	'	'
Total assets	1,716,471		'	1,640,204		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	474,436		'	665,605		'	'	'
Level II | Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	2,914		'	13,298		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	1,671		'	1,728		'	'	'
Level II | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	73,216		'	44,978		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	198		'	1,015		'	'	'
Level II | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	22,006		'	33,668		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	17,022		'	19,314		'	'	'
Level II | Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	250,608		'	164,059		'	'	'
Level II | Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	558,970		'	416,760		'	'	'
Level II | Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	98,866		'	67,672		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	60		'	'	'
Level II | Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	17		'	24		'	'	'
Level II | U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	303,359		'	304,259		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	79,135		'	73,724		'	'	'
Level II | U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level II | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	405,939		'	595,486		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	376,410		'	569,764		'	'	'
Level III	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	167,302		'	119,083		'	'	'
Cash equivalents	'		'	'		'	'	'
Investments	45,579		'	33,245		'	'	'
Total assets	212,881		'	152,328		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	6,581		'	5,218		'	'	'
Level III | Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	100		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Level III | Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	1,433		'	1,429		'	'	'
Level III | Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	656		'	656		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	157,042		'	116,171		'	'	'
Level III | U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'		'	'		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Level III | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	8,071		'	827		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	6,581		'	5,218		'	'	'
Counterparty and Cash Collateral Netting	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	-375,381	[1]	'	-555,838	[1]	'	'	'
Cash equivalents	'	[1]	'	'	[1]	'	'	'
Investments	'	[1]	'	'	[1]	'	'	'
Total assets	-375,381	[1]	'	-555,838	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	-377,518	[1]	'	-570,027	[1]	'	'	'
Counterparty and Cash Collateral Netting | Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	'	[1]	'	'	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	[1]	'	'	[1]	'	'	'
Counterparty and Cash Collateral Netting | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	-375,381	[1]	'	-555,838	[1]	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	-377,518	[1]	'	-570,027	[1]	'	'	'
Total	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	1,533,338		'	1,211,595		'	'	'
Cash equivalents	1,670		'	51,346		'	'	'
Investments	59,572		'	39,055		'	'	'
Total assets	1,594,580		'	1,301,996		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	513,748		'	357,201		'	'	'
Total | Equity securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	28,203		'	16,478		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	58,599		'	27,090		'	'	'
Total | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	73,216		'	44,978		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	198		'	1,015		'	'	'
Total | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	22,106		'	33,668		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	17,022		'	19,314		'	'	'
Total | Taxable securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	250,608		'	164,059		'	'	'
Total | Tax-exempt securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	560,403		'	418,189		'	'	'
Total | Short-term securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	99,522		'	68,328		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	60		'	'	'
Total | Asset-backed securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	157,059		'	116,195		'	'	'
Total | U.S. government agency securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	303,359		'	304,259		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	79,135		'	73,724		'	'	'
Total | U.S. government securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	233		'	4,966		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	353,321		'	231,043		'	'	'
Total | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Financial instruments and other inventory positions owned	38,629		'	40,475		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	5,473		'	4,955		'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	6,581		254	5,218		12,238	7,079	5,665
Financial instruments and other inventory positions sold, but not yet purchased | Convertible securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	'		'	'		'	'	1,171
Financial instruments and other inventory positions sold, but not yet purchased | Fixed income securities	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	'		'	'		'	'	900
Financial instruments and other inventory positions sold, but not yet purchased | Derivative contracts	'		'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'	'		'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$6,581		$254	$5,218		$12,238	$7,079	$3,594
[1]	Represents cash collateral and the impact of netting on a counterparty basis. The Company had no securities posted as collateral to its counterparties.

Fair_Value_of_Financial_Instru5

Fair Value of Financial Instruments - Changes in Fair Value Associated with Level III Financial Instruments (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	$226,339		$116,399		$152,328		$80,554
Purchases	99,763		148,401		464,349		366,364
Sales	-121,554		-146,269		-447,948		-330,951
Transfers in	'		266		'		3,452
Transfers out	-870		-266		-619		-4,529
Realized gains/ (losses)	18,842	[1]	20,559	[1]	38,765	[1]	22,938	[1]
Unrealized gains/ (losses)	-9,639	[1]	5,072	[1]	6,006	[1]	6,334	[1]
Ending balance	212,881		144,162		212,881		144,162
Financial instruments and other inventory positions sold, but not yet purchased	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	254		7,079		5,218		5,665
Purchases	-223		-9,438		-5,873		-19,755
Sales	'		54		745		1,434
Transfers in	'		'		'		'
Transfers out	'		'		'		-1,171
Realized gains/(losses)	223	[1]	9,384	[1]	5,115	[1]	17,375	[1]
Unrealized gains/ (losses)	6,327	[1]	5,159	[1]	1,376	[1]	8,690	[1]
Ending balance	6,581		12,238		6,581		12,238
Financial instruments and other inventory positions sold, but not yet purchased | Convertible securities	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	'		'		'		1,171
Purchases	'		'		'		'
Sales	'		'		'		'
Transfers in	'		'		'		'
Transfers out	'		'		'		-1,171
Realized gains/(losses)	'		'		'		'	[1]
Unrealized gains/ (losses)	'		'		'		'	[1]
Ending balance	'		'		'		'
Financial instruments and other inventory positions sold, but not yet purchased | Fixed income securities	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	'		'		'		900
Purchases	'		'		'		-897
Sales	'		'		'		'
Transfers in	'		'		'		'
Transfers out	'		'		'		'
Realized gains/(losses)	'		'		'		-49	[1]
Unrealized gains/ (losses)	'		'		'		46	[1]
Ending balance	'		'		'		'
Financial instruments and other inventory positions sold, but not yet purchased | Derivative contracts	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	254		7,079		5,218		3,594
Purchases	-223		-9,438		-5,873		-18,858
Sales	'		54		745		1,434
Transfers in	'		'		'		'
Transfers out	'		'		'		'
Realized gains/(losses)	223	[1]	9,384	[1]	5,115	[1]	17,424	[1]
Unrealized gains/ (losses)	6,327	[1]	5,159	[1]	1,376	[1]	8,644	[1]
Ending balance	6,581		12,238		6,581		12,238
Financial instruments and other inventory positions owned	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	172,772		96,535		119,083		59,213
Purchases	99,763		134,401		448,986		352,364
Sales	-111,198		-146,269		-437,592		-330,948
Transfers in	'		266		'		3,452
Transfers out	-251		'		'		-4,263
Realized gains/ (losses)	12,900	[1]	20,559	[1]	32,819	[1]	22,935	[1]
Unrealized gains/ (losses)	-6,684	[1]	5,041	[1]	4,006	[1]	7,780	[1]
Ending balance	167,302		110,533		167,302		110,533
Financial instruments and other inventory positions owned | Convertible securities	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	1,308		3,681		'		'
Purchases	0		27,142		'		30,272
Sales	-1,615		-21,249		'		-23,400
Transfers in	0		'		'		2,960
Transfers out	-251		'		'		'
Realized gains/ (losses)	839		2,051	[1]	'		2,010	[1]
Unrealized gains/ (losses)	-281		836	[1]	'		619	[1]
Ending balance	0		12,461		0		12,461
Financial instruments and other inventory positions owned | Fixed income securities	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	100		'		0		2,815
Purchases	0		'		100		38,433
Sales	0		'		0		-37,149
Transfers in	0		'		0		226
Transfers out	0		'		0		-4,263
Realized gains/ (losses)	0		'		0	[1]	49	[1]
Unrealized gains/ (losses)	0		'		0	[1]	-111	[1]
Ending balance	100		'		100		'
Financial instruments and other inventory positions owned | Tax-exempt securities	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	1,433		2,373		1,429		3,135
Purchases	'		20		1		1,570
Sales	'		-1,102		'		-2,997
Transfers in	'		266		'		266
Transfers out	'		'		'		'
Realized gains/ (losses)	'	[1]	-584	[1]	-266	[1]	-1,156	[1]
Unrealized gains/ (losses)	'	[1]	553	[1]	269	[1]	708	[1]
Ending balance	1,433		1,526		1,433		1,526
Financial instruments and other inventory positions owned | Short-term securities	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	656		394		656		175
Purchases	'		'		'		3,075
Sales	'		'		'		-1,755
Transfers in	'		'		'		'
Transfers out	'		'		'		'
Realized gains/ (losses)	'	[1]	'	[1]	'	[1]	-945	[1]
Unrealized gains/ (losses)	'	[1]	42	[1]	'	[1]	-114	[1]
Ending balance	656		436		656		436
Financial instruments and other inventory positions owned | Asset-backed securities	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	151,396		89,871		116,171		53,088
Purchases	99,763		107,239		448,175		279,014
Sales	-97,246		-122,943		-424,274		-262,383
Transfers in	0		0		'		'
Transfers out	0		0		'		'
Realized gains/ (losses)	-276		18,117		20,562	[1]	19,713	[1]
Unrealized gains/ (losses)	3,405		3,186		-3,592	[1]	6,038	[1]
Ending balance	157,042		95,470		157,042		95,470
Financial instruments and other inventory positions owned | Derivative contracts	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	17,879		216		827		'
Purchases	0		0		710		'
Sales	-12,337		-975		-13,318		-3,264
Transfers in	0		0		'		'
Transfers out	0		0		'		'
Realized gains/ (losses)	12,337		975		12,523	[1]	3,264	[1]
Unrealized gains/ (losses)	-9,808		424		7,329	[1]	640	[1]
Ending balance	8,071		640		8,071		640
Investments	'		'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'		'
Beginning balance	53,567		19,864		33,245		21,341
Purchases	'		14,000		15,363		14,000
Sales	-10,356		'		-10,356		-3
Transfers in	'		'		'		'
Transfers out	-619		-266		-619		-266
Realized gains/ (losses)	5,942	[1]	'	[1]	5,946	[1]	3	[1]
Unrealized gains/ (losses)	-2,955	[1]	31	[1]	2,000	[1]	-1,446	[1]
Ending balance	$45,579		$33,629		$45,579		$33,629
[1]	Realized and unrealized gains/(losses) related to financial instruments, with the exception of customer matched-book derivatives, are reported in institutional brokerage on the consolidated statements of operations. Realized and unrealized gains/(losses) related to customer matched-book derivatives are reported in investment banking. Realized and unrealized gains/(losses) related to investments are reported in investment banking revenues or other income/(loss) on the consolidated statements of operations

Variable_Interest_Entities_Add

Variable Interest Entities - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Variable Interest Entities Disclosure [Abstract]	'	'
Variable interest entities, aggregate investment	$109,500,000	$96,900,000
Remaining capital commitments to investment vehicles	35,900,000	'
Variable Interest Entity Nonconsolidated Total Assets	700,000,000	800,000,000
Variable interest entities, exposure to loss	6,400,000	'
VIE liabilities	$0	$0

Receivables_from_and_Payables_2

Receivables from and Payables to Brokers, Dealers and Clearing Organizations - Amounts Receivable from Brokers, Dealers and Clearing Organizations (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Disclosure Amounts Receivable From Brokers Dealers And Clearing Organizations [Abstract]	'	'
Receivable arising from unsettled securities transactions	$112,613	$66,426
Deposits paid for securities borrowed	36,395	32,163
Receivable from clearing organizations	22,025	17,655
Deposits with clearing organizations	47,799	24,717
Securities failed to deliver	9,222	5,440
Other	14,249	1,716
Brokers, dealers and clearing organizations	$242,303	$148,117

Receivables_from_and_Payables_3

Receivables from and Payables to Brokers, Dealers and Clearing Organizations - Amounts Payable to Brokers, Dealers and Clearing Organizations (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Disclosure Amounts Payable To Brokers Dealers And Clearing Organizations [Abstract]	'	'
Payable arising from unsettled securities transactions	$96,097	$24,643
Payable to clearing organizations	14,265	5,763
Securities failed to receive	7,919	7,459
Other	8,071	22,290
Brokers, dealers and clearing organizations	$126,352	$60,155

Collateralized_Securities_Tran2

Collateralized Securities Transactions - Summary of Repurchase Liabilities, Fair Market Value of Related Collateral Pledged and Interest Rate Charged (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	$78,914
Fair Market Value	84,008
Maturity Overnight [Member] | Taxable securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	4,062
Fair Market Value	5,625
Interest Rate	1.68%
On demand maturities | U.S. government agency securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	74,852
Fair Market Value	$78,383
Minimum | On demand maturities | U.S. government agency securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	0.30%
Maximum | On demand maturities | U.S. government agency securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	0.55%

Collateralized_Securities_Tran3

Collateralized Securities Transactions - Offsetting Assets and Liabilities (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Offsetting Assets and Liabilities [Line Items]	'		'
ReverseRepurchaseGrossAmount	$227,423		'
Offsetting Derivative Assets [Abstract]	'		'
Gross Amounts Offset on the Consolidated Statements of Financial Condition	-41,999		'
Securities purchased under agreements to resell	185,424		145,433
Repurchase Agmt Eligible Did Not Offset	0		'
Collateral Held on Reverse Repurchase Agreement Offset Disclosure	-185,424	[1]	'
Reverse Repurchase agreements netted with collateral	0		'
SecuritiesBorrowedGrossAmount	36,395		'
Securities borrowed, Offset Amount	0	[2]	'
Net Amounts Presented on the Consolidated Statements of Financial Condition	36,395	[2]	'
Gross Amounts Not Offset on the Consoldiated Statements of Financial Condition, Financial Instruments	0	[2]	'
Gross Amounts Not Offset on the Consoldiated Statements of Financial Condition, Collateral Received	-36,395	[1],[2]	'
Net Amount	0	[2]	'
Offsetting Derivative Liabilities [Abstract]	'		'
Securities sold under agreements to repurchase	36,915		50,000
Gross Amounts Not Offset on the Consolidated Statements of Financial Condition, Collateral Pledged	-36,915	[3]	'
Net Amount	0		'
Repurchase agreements	'		'
Offsetting Derivative Liabilities [Abstract]	'		'
Gross Recognized Liabilities	78,914		'
Gross Amounts Offset on the Consolidated Statements of Financial Condition	-41,999		'
Gross Amounts Not Offset on the Consolidated Statements of Financial Condition, Financial Instruments	$0		'
[1]	Includes securities received by the Company from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default.
[2]	ecurities borrowed are included in receivables from brokers, dealers and clearing organizations on the consolidated statements of financial condition. See Note 9 for additional information on receivables from brokers, dealers and clearing organizations.
[3]	Includes the fair value of securities pledged by the Company to the counterparty. These securities are included on the consolidated statements of financial condition unless the Company defaults.

Collateralized_Securities_Tran4

Collateralized Securities Transactions - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Collateralized Securities Transactions Disclosure [Abstract]	'	'
Securities purchased under agreements to resell, securities borrowed and margin agreements on terms that permit to repledge or resell the securities to others	$268,000,000	$186,100,000
Securities either pledged or otherwise transferred to others in connection with financing activities or to satisfy commitments under financial instruments and other inventory positions sold, but not yet purchased	258,000,000	174,400,000
Securities Loaned	$0	'

Other_Assets_Detail

Other Assets (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'	'
Net deferred income tax assets	$27,689	$33,622
Investments at fair value	59,572	39,055
Investments at cost	25,303	26,364
Investments accounted for under the equity method	20,273	20,353
Income tax receivables	5,656	5,448
Prepaid expenses	3,253	3,840
Other	1,672	1,015
Total other assets	$143,418	$129,697

Other_Assets_Additional_Inform

Other Assets - Additional Information (Detail) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Estimated fair market value of investments carried at cost	$44.70

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Changes in Carrying Value of Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Goodwill	'	'	'	'
Goodwill beginning balance	'	'	$196,844	'
Goodwill acquired	'	'	13,956	'
Impairment charge	'	'	0	'
Goodwill ending balance	210,800	'	210,800	'
Intangible assets	'	'	'	'
Intangible assets beginning balance	'	'	41,258	'
Intangible assets acquired	6,924	'	6,924	'
Amortization of intangible assets	-2,899	-1,736	-6,221	-5,208
Intangible assets ending balance	41,961	'	41,961	'
Asset Management	'	'	'	'
Goodwill	'	'	'	'
Goodwill beginning balance	'	'	196,844	'
Goodwill acquired	'	'	'	'
Impairment charge	'	'	'	'
Goodwill ending balance	196,844	'	196,844	'
Intangible assets	'	'	'	'
Intangible assets beginning balance	'	'	41,258	'
Intangible assets acquired	0	'	0	'
Amortization of intangible assets	-1,661	-1,736	-4,983	-5,208
Intangible assets ending balance	36,275	'	36,275	'
Capital Markets	'	'	'	'
Goodwill	'	'	'	'
Goodwill beginning balance	'	'	0	'
Goodwill acquired	'	'	13,956	'
Impairment charge	'	'	0	'
Goodwill ending balance	13,956	'	13,956	'
Intangible assets	'	'	'	'
Intangible assets beginning balance	'	'	0	'
Intangible assets acquired	6,924	'	6,924	'
Amortization of intangible assets	-1,238	0	-1,238	0
Intangible assets ending balance	$5,686	'	$5,686	'

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Additional Information (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Line Items]	'
Finite-Lived Customer Relationships, Gross	$6,924
Capital Markets	'
Goodwill And Intangible Assets Disclosure [Line Items]	'
Finite-Lived Customer Relationships, Gross	6,924
Customer Relationships | Capital Markets	'
Goodwill And Intangible Assets Disclosure [Line Items]	'
Finite-Lived Customer Relationships, Gross	6,200
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'1 year 8 months
Noncompete Agreements | Capital Markets	'
Goodwill And Intangible Assets Disclosure [Line Items]	'
Finite-Lived Customer Relationships, Gross	$700
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'3 years

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Aggregate Future Intangible Asset Amortization Expense (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]	'
Remainder of 2013	$3,147
2014	8,200
2015	7,050
2016	6,219
2017	5,230
Thereafter	9,255
Total	$39,101

ShortTerm_Financing_Summary_of

Short-Term Financing - Summary of Short Term Financing and Weighted Average Interest Rate on Borrowings (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Short-term Debt [Line Items]	'	'
Oustanding Balance	$663,289	$477,014
Commercial paper (secured)	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	345,733	304,439
Weighted Average Interest Rate	1.47%	1.65%
Prime broker arrangement	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	223,556	172,575
Weighted Average Interest Rate	0.92%	0.98%
Line of Credit [Member]	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	$94,000	$0
Weighted Average Interest Rate	1.50%	'

ShortTerm_Financing_Additional

Short-Term Financing - Additional Information (Detail) (USD $)

0 Months Ended

9 Months Ended

9 Months Ended

Dec. 29, 2010

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Commercial paper (secured)

Commercial paper (secured)

Commercial paper (secured)

Commercial paper (secured)

Commercial paper (secured)

Commercial paper (secured)

Commercial paper (secured)

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Committed Credit Facility [Member]

Committed Credit Facility [Member]

program

Minimum

Maximum

CP Series A

CP Series II A

CP Series III A

Uncommitted Credit Facility [Member]

Committed Credit Facility [Member]

Covenant Requirement

banks

Short-term Debt [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior secured commercial paper notes, maturity period

'

'

'

'

'

'27 days

'270 days

'

'

'

'

'

'

'

'

'

Number of commercial paper programs

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average maturity period

'

'

'

'

'

'

'

'128 days

'108 days

'32 days

'

'

'

'

'

'

Debt term

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

Line of credity, maximum borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

$185,000,000

$250,000,000

$250,000,000

'

Minimum net capital required

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

120,000,000

Short-term financing

'

$663,289,000

$477,014,000

$345,733,000

$304,439,000

'

'

'

'

'

$94,000,000

$0

$94,000,000

$0

'

'

Number of banks

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

Variable_Rate_Senior_Notes_Add

Variable Rate Senior Notes - Additional Information (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Nov. 30, 2012	Sep. 30, 2013	Nov. 30, 2012	Sep. 30, 2013	Nov. 30, 2012	Sep. 30, 2013
		Senior Notes	Senior Notes	Senior Notes	Senior Notes	Senior Notes	Senior Notes
		class	Class A Variable Rate Senior Notes Due May 2014	Class A Variable Rate Senior Notes Due May 2014	Class B Variable Rate Senior Notes Due November 2015	Class B Variable Rate Senior Notes Due November 2015	Covenant Requirement
			Three-Month LIBOR	Three-Month LIBOR	Three-Month LIBOR	Three-Month LIBOR
Debt Instrument [Line Items]	'	'	'	'	'	'	'
Face amount	'	$125,000,000	'	$50,000,000	'	$75,000,000	'
Number of classes of notes	'	2	'	'	'	'	'
Basis spread on variable rate	'	'	4.00%	'	4.50%	'	'
Note purchase agreement, days to pay interest	'5 days	'	'	'	'	'	'
Note purchase agreement, event of default, maximum indebtedness	10,000,000	'	'	'	'	'	'
Minimum net capital required	'	'	'	'	'	'	$120,000,000

Bank_Syndicated_Financing_Addi

Bank Syndicated Financing - Additional Information (Detail) (USD $)	0 Months Ended	23 Months Ended
In Millions, unless otherwise specified	Dec. 29, 2010	Nov. 30, 2012
Debt Instrument [Line Items]	'	'
Debt term	'3 years	'
Credit agreement, interest rate margin above federal funds rate	0.50%	'
Credit agreement, interest rate margin above one-month LIBOR rate	1.00%	'
Credit agreement, applicable margin rate, minimum	1.50%	'
Credit agreement, applicable margin rate, maximum	3.00%	'
Nonrefundable commitment fee, percentage	'	0.50%
Term Loan	'	'
Debt Instrument [Line Items]	'	'
Bank syndicated financing	100	'
Revolving credit facility	'	'
Debt Instrument [Line Items]	'	'
Bank syndicated financing	50	'

Legal_Contingencies_Additional

Legal Contingencies - Additional Information (Detail)	Sep. 30, 2013
	district
California	'
Loss Contingencies [Line Items]	'
Number of districts	18
New York	'
Loss Contingencies [Line Items]	'
Number of districts	2

Restructuring_Additional_Infor

Restructuring - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]	'	'
Restructuring-related expense	$2.90	$3.60
Severance Costs	2.1	2.4
Leased Office Space [Member]	'	'
Restructuring Cost and Reserve [Line Items]	'	'
Other Restructuring Costs	0.5	1.2
Contract Termination [Member]	'	'
Restructuring Cost and Reserve [Line Items]	'	'
Other Restructuring Costs	$0.30	'

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stockholders Equity Note [Line Items]	'	'	'	'
Repurchase of common stock, authorized amount	'	$100,000,000	'	'
Treasury Stock, Shares, Acquired	'	'	1,683,094	'
Treasury Stock, Shares, Acquired as Pecent of Outstanding Common Stock	'	'	11.10%	'
Treasury Stock Acquired, Average Cost Per Share	'	'	$32.53	'
Treasury Stock, Value, Acquired, Cost Method	'	'	54,743,000	'
Common stock repurchase authorized, remaining amount	'	'	40,700,000	'
Shares of common stock purchased from restricted stock award related to recipients' employment tax obligations	'	'	377,479	'
Repurchase of common stock for employee tax withholding	'	'	15,204,000	'
Stock Issued During Period, Shares, Treasury Stock Reissued	'	'	96,049	165,241
Compensation and benefits	79,426,000	78,070,000	210,531,000	209,467,000
Reissuance of treasury shares as a result of employee vesting	'	'	770,189	797,296
Retirement Plan	'	'	'	'
Stockholders Equity Note [Line Items]	'	'	'	'
Compensation and benefits	'	'	$3,900,000	$3,800,000

Noncontrolling_Interests_Addit

Noncontrolling Interests - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	$149,629	$56,883
Municipal bond fund	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	128,900	43,700
Merchant banking fund	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	13,300	6,400
Other private equity investments	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	$7,400	$6,800

Noncontrolling_Interest_Rollfo

Noncontrolling Interest - Rollforward (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Beginning Balance	'	'	$790,175	'
Stockholders' Equity Attributable to Parent	'	'	733,292	'
Noncontrolling interest, beginning balance	'	'	56,883	'
Net Income (Loss) Attributable to Parent	5,322	19,664	17,956	29,444
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	7,645	20,329	19,510	32,115
Net income applicable to noncontrolling interests	2,323	665	1,554	2,671
Amortization/issuance of restricted stock	'	'	22,049	'
Repurchase of common stock through share repurchase program	'	'	-54,743	'
Repurchase of common stock for employee tax withholding	'	'	-15,204	'
Issuance of treasury shares for 401k match	'	'	3,939	3,814
Shares reserved to meet deferred compensation obligations	'	'	60	'
Other comprehensive income	137	122	16	131
Fund capital contributions, net	'	'	91,192	'
Noncontrolling interest, ending balance	149,629	'	149,629	'
Stockholders' Equity Attributable to Parent	707,365	'	707,365	'
Ending Balance	856,994	'	856,994	'
Parent	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Amortization/issuance of restricted stock	'	'	22,049	'
Repurchase of common stock through share repurchase program	'	'	-54,743	'
Repurchase of common stock for employee tax withholding	'	'	-15,204	'
Issuance of treasury shares for 401k match	'	'	3,939	'
Shares reserved to meet deferred compensation obligations	'	'	60	'
Other comprehensive income	'	'	16	'
Fund capital contributions, net	'	'	0	'
Noncontrolling Interests	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Amortization/issuance of restricted stock	'	'	0	'
Repurchase of common stock through share repurchase program	'	'	0	'
Repurchase of common stock for employee tax withholding	'	'	0	'
Issuance of treasury shares for 401k match	'	'	0	'
Shares reserved to meet deferred compensation obligations	'	'	0	'
Other comprehensive income	'	'	0	'
Fund capital contributions, net	'	'	$91,192	'

Compensation_Plans_Summary_of_

Compensation Plans - Summary of Outstanding Equity Awards (Details)	Sep. 30, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	1,369,057	'
Total restricted stock outstanding	1,589,513	'
Stock options outstanding	470,065	486,563
Restricted Stock Units	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Leadership grants	290,536	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	1,310,747	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Annual grants	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	879,123	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Sign-on grants	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	431,624	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Retention Grant [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	0	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Performance Shares [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	0	'
2010 Employment Inducement Award Plan	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	58,310	'
acquisition related [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total restricted stock outstanding	220,456	'

Compensation_Plans_RSU_Valuati

Compensation Plans - RSU Valuation Assumptions (Details) (Restricted Stock Units)	9 Months Ended
	Sep. 30, 2013
Grant Year 2013	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk-free Interest Rate	0.40%
Expected Stock Price Volatility	44.00%
Grant Year 2012	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk-free Interest Rate	0.38%
Expected Stock Price Volatility	47.60%

Compensation_Plans_Unvested_Re

Compensation Plans - Unvested Restricted Stock (Details) (Restricted Stock, USD $)	9 Months Ended
	Sep. 30, 2013
Restricted Stock	'
Unvested Restricted Stock or Stock Units	'
Beginning Balance	2,322,438
Granted	656,934
Vested	-1,140,292
Cancelled	-249,567
Ending Balance	1,589,513
Weighted Average Grant Date Fair Value (in dollars per share)	'
Beginning Balance	$37.01
Granted	$38.45
Vested	$39.99
Cancelled	$38.46
Ending Balance	$31.10

Compensation_Plans_Unvested_Re1

Compensation Plans - Unvested Restricted Stock Units (Details) (Restricted Stock Units, USD $)	9 Months Ended
	Sep. 30, 2013
Restricted Stock Units	'
Unvested Restricted Stock or Stock Units	'
Beginning Balance	173,271
Granted	117,265
Vested	0
Cancelled	0
Ending Balance	290,536
Weighted Average Grant Date Fair Value (in dollars per share)	'
Beginning Balance	$12.12
Granted	$21.32
Vested	$0
Cancelled	$0
Ending Balance	$15.83

Compensation_Plans_Stock_Optio

Compensation Plans - Stock Options (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Options Outstanding	'	'
Beginning Balance	486,563	'
Granted	0	'
Exercised	0	'
Cancelled	-16,498	'
Ending Balance	470,065	486,563
Options exercisable at period end	470,065	'
Weighted Average Exercise Price (in dollars per share)	'	'
Beginning Balance	$44.76	'
Granted	$0	'
Exercised	$0	'
Cancelled	$42.91	'
Ending Balance	$44.82	$44.76
Options exercisable at period end	$44.82	'
Weighted Average Remaining Contractual Term (in Years)	'	'
Weighted Average Remaining Contractual Term (in Years)	'2 years 2 months 12 days	'2 years 10 months 24 days
Options exercisable at period end	'2 years 2 months 12 days	'
Aggregate Intrinsic Value	'	'
Aggregate Intrinsic Value of Stock Options	$147,071	$94,150
Options exercisable at end of period	$147,071	'

Compensation_Plans_Additional_

Compensation Plans - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2010

Sep. 30, 2013

15-May-12

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2010

plan

plan

Minimum

Maximum

Maximum

Annual grants

Annual grants

Retention Grant [Member]

Restricted Stock Units

Restricted Stock Units

Restricted Stock Units

Restricted Stock Units

Restricted Stock

Stock Options

Amended And Restated 2003 Annual And Long -Term Incentive Plan

Amended And Restated 2003 Annual And Long -Term Incentive Plan

2010 Employment Inducement Award Plan

New Employees [Member]

New Employees [Member]

Maximum

Maximum

Maximum

Award Earned Based on Shareholder Return Relative to Predetermined Peer Group

Award Earned Based on Total Shareholder Return

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of stock-based compensation plans

2

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity award grants authorized

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,000,000

'

Shares available for future issuance

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,100,000

'

'

Award vesting period in years

'

'

'

'

'

'

'

'3 years

'3 years

'5 years

'

'

'

'

'

'

'

'

'5 years

Annual grant expense period

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

'

'

'

'

'

Forfeitures recorded as a result of violating the post-termination restrictions

$100,000

$200,000

$800,000

$1,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted stock units, performance period

'

'

'

'

'

'

'

'

'

'

'36 months

'

'

'

'

'

'

'

'

Weighted average period over which restricted stock expense expected to be recognized

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'2 years 11 months 8 days

'

'

'

'

Award earning percentage

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

Number of years risk free interest rate

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

Term of stock options

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted shares granted to ARI employees, value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,000,000

Restricted shares granted, share

'

'

'

'

'

'

'

'

'

'

'

117,265

'

'

656,934

'

'

'

158,801

Compensation expense related to employee restricted stock awards

6,100,000

9,100,000

11,200,000

15,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax benefit related to compensation costs for stock-based compensation arrangements

2,400,000

3,500,000

4,400,000

6,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized compensation cost related to restricted stock

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$14,600,000

$0

'

'

'

Acquisition related compensation awards vesting period

'

'

'3 years

'

'2 years

'

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Earnings Per Share [Abstract]	'		'		'		'
Net income from continuing operations	$6,851		$14,493		$21,877		$31,510
Net income/(loss) from discontinued operations	-1,529		5,171		-3,921		-2,066
Net income applicable to Piper Jaffray Companies	5,322		19,664		17,956		29,444
Earnings allocated to participating securities	-496	[1]	-2,824	[1]	-1,793	[1]	-4,293	[1]
Net income applicable to Piper Jaffray Companies' common shareholders	$4,826		$16,840		$16,163		$25,151
Shares for basic and diluted calculations:	'		'		'		'
Average shares used in basic computation	14,621,000		15,210,000		15,271,000		15,736,000
Incremental common share attributable to share-based payment arrangements	5,000		0		13,000		0
Average shares used in diluted computation	14,626,000		15,210,000		15,284,000		15,736,000
Earnings/(loss) per basic common share	'		'		'		'
Income from continuing operations	$0.42		$0.82		$1.29		$1.71
Loss from discontinued operations	($0.09)		$0.29		($0.23)		($0.11)
Earnings per basic common share	$0.33		$1.11		$1.06		$1.60
Earnings/(loss) per diluted common share	'		'		'		'
Income from continuing operations	$0.42		$0.82		$1.29		$1.71
Loss from discontinued operations	($0.09)		$0.29		($0.23)		($0.11)
Earnings per diluted common share	$0.33		$1.11		$1.06		$1.60
Weighted average participating shares outstanding	1,504,665		2,550,888		1,695,130		2,686,255
[1]	Represents the allocation of earnings to participating securities. Losses are not allocated to participating securities. Participating securities include all of the Company’s unvested restricted shares. The weighted average participating shares outstanding were 1,504,665 and 2,550,888 for the three months ended September 30, 2013 and 2012, respectively, and 1,695,130 and 2,686,255 for the nine months ended September 30, 2013 and 2012, respectively.

Segment_Reporting_Reportable_S

Segment Reporting - Reportable Segment Financial Results (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Segment Reporting Information [Line Items]	'		'		'		'
Investment banking	$62,373		$51,083		$155,581		$148,536
Institutional sales and trading	37,218		58,719		101,038		134,006
Total management and performance fees	18,309		16,136		54,551		48,699
Other income/(loss)	4,679		235		10,942		1,242
Net revenues	128,314		131,505		337,619		348,041
Operating expenses	116,254		106,153		304,058		301,812
Segment pre-tax operating income/(loss)	12,060		25,352		33,561		46,229
Pre-tax operating margin	9.40%		19.30%		9.90%		13.30%
Intangible asset amortization expense	2,899		1,736		6,221		5,208
Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Investment banking	63,033		51,671		157,236		150,409
Institutional sales and trading	43,397		64,617		118,526		151,362
Other income/(loss)	3,833		-1,039		7,519		-2,141
Net revenues	110,263		115,249		283,281		299,630
Operating expenses	103,906		94,671		266,301		266,529
Segment pre-tax operating income/(loss)	6,357		20,578		16,980		33,101
Pre-tax operating margin	5.80%		17.90%		6.00%		11.00%
Intangible asset amortization expense	1,238		0		1,238		0
Asset Management	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Management fees	17,547		15,800		52,212		47,213
Performance fees	60		22		716		664
Total management and performance fees	17,607		15,822		52,928		47,877
Other income/(loss)	444		434		1,410		534
Net revenues	18,051		16,256		54,338		48,411
Operating expenses	12,348	[1]	11,482	[1]	37,757	[1]	35,283	[1]
Segment pre-tax operating income/(loss)	5,703		4,774		16,581		13,128
Pre-tax operating margin	31.60%		29.40%		30.50%		27.10%
Intangible asset amortization expense	1,661		1,736		4,983		5,208
Financing | Equities | Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Investment banking	30,010		18,781		66,085		55,141
Financing | Debt | Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Investment banking	12,808		16,573		51,971		53,598
Advisory Services | Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Investment banking	20,215		16,317		39,180		41,670
Equity securities | Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Institutional sales and trading	22,960		17,927		65,087		55,589
Debt securities | Capital Markets	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Institutional sales and trading	$20,437		$46,690		$53,439		$95,773
[1]	Operating expenses include intangible asset amortization expense as set forth in the table below: Three Months Ended Nine Months Ended September 30, September 30,(Dollars in thousands)2013 2012 2013 2012Capital Markets$1,238 $— $1,238 $—Asset Management1,661 1,736 4,983 5,208Total intangible asset amortization expense$2,899 $1,736 $6,221 $5,208

Segment_Reporting_Net_Revenues

Segment Reporting - Net Revenues by Geographic Locations (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	$128,314	$131,505	$337,619	$348,041
United States	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	126,458	128,580	329,379	339,727
Europe	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	$1,856	$2,925	$8,240	$8,314

Segment_Reporting_LongLived_As

Segment Reporting - Long-Lived Assets By Geographic Region (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	$295,729	$286,813
United States	'	'
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	294,936	285,682
Europe	'	'
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	$793	$1,131

Net_Capital_Requirements_and_O1

Net Capital Requirements and Other Regulatory Matters - Additional Information (Detail) (USD $)	Sep. 30, 2013
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]	'
Net capital requirement	$1,000,000
Net capital requirement, percentage of aggregate debit balances arising from customer transactions	2.00%
Net capital requirement, percent of aggregate debit balances under restriction on business expansion or dividend payment	5.00%
Net capital	150,200,000
Amount of capital that exceeds the minimum net capital required	149,200,000
Committed Credit Facility [Member]	'
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]	'
Revolving credit facility	250,000,000
Committed Credit Facility [Member] | Covenant Requirement	'
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]	'
Minimum net capital required	$120,000,000

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Effective income tax rate	29.60%	41.30%	31.60%	27.70%
Changes in income tax expense due to unrecognized tax benefits decreases	'	$7.10	'	'
Write-off of a deferred tax asset related to equity grants that were forfeited or vested at a share price lower than the grant date share price	'	'	'	4
Income tax benefit from discontinued operations	($1)	($22)	($1.20)	($21.70)