Piper Sandler Companies (PIPR) 10-Q 6 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 24, 2014
Document and Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
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	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	16,285,976

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Cash and cash equivalents	$14,947	$123,683
Cash and cash equivalents segregated for regulatory purposes	38,029	43,012
Receivables:	'	'
Customers	25,669	11,633
Brokers, dealers and clearing organizations	291,190	127,113
Securities purchased under agreements to resell	263,680	167,875
Financial instruments and other inventory positions owned	459,624	406,513
Financial instruments and other inventory positions owned and pledged as collateral	1,023,970	957,515
Total financial instruments and other inventory positions owned	1,483,594	1,364,028
Fixed assets (net of accumulated depreciation and amortization of $46,128 and $62,311, respectively)	17,373	16,114
Goodwill	211,878	210,634
Intangible assets (net of accumulated amortization of $38,823 and $31,869, respectively)	32,976	39,930
Investments	125,167	112,043
Other assets	96,037	102,092
Total assets	2,600,540	2,318,157
Liabilities and Shareholders’ Equity	'	'
Short-term financing	338,795	514,711
Variable rate senior notes	125,000	125,000
Payables:	'	'
Customers	35,944	33,109
Brokers, dealers and clearing organizations	84,344	27,722
Securities sold under agreements to repurchase	66,973	4,397
Financial instruments and other inventory positions sold, but not yet purchased	768,991	512,833
Accrued compensation	181,322	159,928
Other liabilities and accrued expenses	53,823	58,385
Total liabilities	1,655,192	1,436,085
Shareholders’ equity:	'	'
Common stock, $0.01 par value: Shares authorized: 100,000,000 at September 30, 2014 and December 31, 2013; Shares issued: 19,523,371 at September 30, 2014 and 19,537,127 at December 31, 2013; Shares outstanding: 15,108,607 at September 30, 2014 and 14,383,418 at December 31, 2013	195	195
Additional paid-in capital	737,449	740,321
Retained earnings	214,522	163,893
Less common stock held in treasury, at cost: 4,414,764 shares at September 30, 2014 and 5,153,709 shares at December 31, 2013	-148,286	-170,629
Accumulated other comprehensive income	753	896
Total common shareholders’ equity	804,633	734,676
Noncontrolling interests	140,715	147,396
Total shareholders’ equity	945,348	882,072
Total liabilities and shareholders’ equity	$2,600,540	$2,318,157

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Accumulated depreciation and amortization on fixed assets	$46,128	$62,311
Accumulated amortization on intangible assets	$38,823	$31,869
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	19,523,371	19,537,127
Common stock, shares outstanding	15,108,607	14,383,418
Common stock held in treasury, shares	4,414,764	5,153,709

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:	'	'	'	'
Investment banking	$94,911	$62,848	$287,198	$156,924
Institutional brokerage	35,923	35,318	114,485	100,076
Asset management	21,595	18,701	64,820	55,584
Interest	10,828	12,360	36,935	35,469
Investment income	2,690	5,279	12,379	8,285
Total revenues	165,947	134,506	515,817	356,338
Interest expense	6,521	6,192	18,227	18,719
Net revenues	159,426	128,314	497,590	337,619
Non-interest expenses:	'	'	'	'
Compensation and benefits	97,180	79,426	300,745	210,531
Occupancy and equipment	8,312	6,509	22,151	18,869
Communications	5,661	5,778	17,048	16,040
Floor brokerage and clearance	1,905	2,109	5,527	6,506
Marketing and business development	6,827	5,447	19,787	16,384
Outside services	9,155	8,082	27,837	23,745
Restructuring and integration costs	0	3,823	0	3,823
Intangible asset amortization expense	2,318	2,899	6,954	6,221
Other operating expenses	2,376	2,181	8,719	1,939
Total non-interest expenses	133,734	116,254	408,768	304,058
Income from continuing operations before income tax expense	25,692	12,060	88,822	33,561
Income tax expense	8,596	2,886	28,472	10,130
Income from continuing operations	17,096	9,174	60,350	23,431
Discontinued operations:	'	'	'	'
Loss from discontinued operations, net of tax	0	-1,529	0	-3,921
Net income	17,096	7,645	60,350	19,510
Net income applicable to noncontrolling interests	2,428	2,323	9,721	1,554
Net income applicable to Piper Jaffray Companies	14,668	5,322	50,629	17,956
Net income applicable to Piper Jaffray Companies’ common shareholders	13,552	4,826	46,386	16,163
Amounts applicable to Piper Jaffray Companies	'	'	'	'
Net income from continuing operations	14,668	6,851	50,629	21,877
Net loss from discontinued operations	0	-1,529	0	-3,921
Net income applicable to Piper Jaffray Companies	$14,668	$5,322	$50,629	$17,956
Earnings/(loss) per basic common share	'	'	'	'
Income from continuing operations	$0.90	$0.42	$3.12	$1.29
Loss from discontinued operations	$0	($0.09)	$0	($0.23)
Earnings per basic common share	$0.90	$0.33	$3.12	$1.06
Earnings/(loss) per diluted common share	'	'	'	'
Income from continuing operations	$0.90	$0.42	$3.11	$1.29
Loss from discontinued operations	$0	($0.09)	$0	($0.23)
Earnings per diluted common share	$0.90	$0.33	$3.11	$1.06
Weighted average number of common shares outstanding	'	'	'	'
Basic	15,066	14,621	14,880	15,271
Diluted	15,129	14,626	14,934	15,284

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$17,096	$7,645	$60,350	$19,510
Other comprehensive income/(loss), net of tax:	'	'	'	'
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	0	38	0	38
Foreign currency translation adjustment	-399	175	-143	54
Other Comprehensive Income (Loss), Net of Tax	-399	137	-143	16
Comprehensive income	16,697	7,782	60,207	19,526
Comprehensive income applicable to noncontrolling interests	2,428	2,323	9,721	1,554
Comprehensive income applicable to Piper Jaffray Companies	$14,269	$5,459	$50,486	$17,972

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating Activities:	'	'
Net income/(loss)	$60,350	$19,510
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:	'	'
Depreciation and amortization of fixed assets	3,992	4,300
Deferred income taxes	-2,487	5,933
Loss on sale of FAMCO	0	-1,876
Share-based and deferred compensation	21,067	11,012
Amortization of intangible assets	6,954	6,221
Amortization of forgivable loans	3,961	4,827
Decrease/(increase) in operating assets:	'	'
Cash and cash equivalents segregated for regulatory purposes	4,983	5,999
Receivables:	'	'
Customers	-14,036	-17,580
Brokers, dealers and clearing organizations	-164,077	-94,186
Securities purchased under agreements to resell	-95,805	-81,990
Net financial instruments and other inventory positions owned	136,592	-163,710
Investments	-13,124	-19,375
Other assets	3,298	2,945
Payables:	'	'
Customers	2,835	-1,229
Brokers, dealers and clearing organizations	56,622	65,071
Accrued compensation	25,741	-26,425
Other liabilities and accrued expenses	-4,559	-23,566
Increase (Decrease) in Liabilities Held-for-sale	0	-465
Increase (Decrease) in Assets Held-for-sale	0	605
Net cash provided by/(used in) operating activities	32,307	-300,227
Investing Activities:	'	'
Payments to Acquire Businesses, Net of Cash Acquired	0	-24,726
Sale of FAMCO	0	250
Purchases of fixed assets, net	-5,270	-3,257
Net cash used in investing activities	-5,270	-27,733
Financing Activities:	'	'
Increase/(decrease) in short-term financing	-175,916	186,275
Proceeds from Issuance of Senior Long-term Debt	50,000	0
Repayments of Long-term Debt	-50,000	0
Increase in securities sold under agreements to repurchase	62,576	28,914
Increase/(decrease) in noncontrolling interests	-16,402	91,192
Repurchase of common stock	-10,563	-69,947
Excess tax benefit from share-based compensation	1,006	39
Proceeds from stock option transactions	3,644	0
Net cash provided by/(used in) financing activities	-135,655	236,473
Currency adjustment:	'	'
Effect of exchange rate changes on cash	-118	77
Net decrease in cash and cash equivalents	-108,736	-91,410
Cash and cash equivalents at beginning of year	123,683	105,371
Cash and cash equivalents at end of year	14,947	13,961
Supplemental disclosure of cash flow information –	'	'
Interest	17,116	17,938
Income taxes	45,284	2,870
Non-cash financing activities –	'	'
Issuance of common stock for retirement plan obligations: 103,598 shares and 96,049 shares for the nine months ended September 30, 2014 and 2013, respectively	4,156	3,939
Issuance of restricted common stock for annual equity award: 402,074 shares and 431,582 shares for the nine months ended September 30, 2014 and 2013, respectively	$16,131	$17,699

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]	'	'
Number of common stock issued for retirement plan obligations	103,598	96,049
Number of restricted common stock issued for annual equity award	402,074	431,582

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2014
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 and investing activities, which focus on proprietary investments in a variety of securities, including municipal bonds, mortgage-backed securities, and equity securities, and merchant banking activities involving 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 to 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 in 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.
	Reclassifications
	In 2013, the Company reclassified interest revenue and expense associated with its derivative contracts to investment banking or institutional brokerage revenues within the consolidated statements of operations to more accurately reflect the nature and intent of the derivative instrument. The Company reclassified $3.9 million and $8.5 million of interest revenue and $4.3 million and $9.8 million of interest expense for the three and nine months ended September 30, 2013, respectively. This change had no effect on net revenues, net income, shareholders’ equity or cash flows for the periods presented.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
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, 2013 for a full description of the Company's significant accounting policies.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	Adoption of New Accounting Standards
	Investment Companies
	In June 2013, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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 was effective for the Company as of January 1, 2014. The adoption of ASU 2013-08 did not impact the Company's results of operations, financial position or disclosures.
	Future Adoption of New Accounting Standards
	Discontinued Operations
	In April 2014, the FASB issued ASU No. 2014-08, "Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity," ("ASU 2014-08") amending FASB Accounting Standards Codification Topic 205-20, "Discontinued Operations" ("ASC 205-20"). The amended guidance changes the criteria for reporting discontinued operations and requires new disclosures. ASU 2014-08 is effective for annual and interim periods beginning on or after December 15, 2014, and will be applied prospectively.
	Revenue Recognition
	In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)," ("ASU 2014-09") which supersedes current revenue recognition guidance, including most industry-specific guidance. ASU 2014-09 requires a company to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods and services. The guidance also requires additional disclosures regarding the nature, amount, timing and uncertainty of revenue that is recognized. ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2016. Early adoption is not permitted. The Company is evaluating the impact of the new guidance on its consolidated financial statements.
	Repurchase Agreements
	In June 2014, the FASB issued ASU No. 2014-11, "Transfers and Servicing (Topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures," ("ASU 2014-11") amending FASB Accounting Standards Codification Topic 860, "Transfers and Servicing." The amended guidance changes the accounting for repurchase-to-maturity transactions and repurchase financing arrangements. The guidance also requires new disclosures for certain transfers accounted for as sales and collateral supporting transactions that are accounted for as secured borrowings. ASU 2014-11 is effective for annual and interim periods beginning after December 15, 2014, except for the disclosures related to secured borrowings, which are effective for annual periods beginning after December 15, 2014, and for interim periods beginning after March 15, 2015. The adoption of ASU 2014-11 is not expected to have a material impact on the Company's results of operations or financial position, but may impact the Company's disclosures.
	Going Concern
	In August 2014, the FASB issued ASU No. 2014-15, "Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern" ("ASU 2014-15"). ASU 2014-15 provides guidance about management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related disclosures thereon. The guidance is effective for annual and interim periods ending after December 15, 2016, with early adoption permitted. The adoption of ASU 2014-15 is not expected to impact the Company's results of operations, financial position or disclosures.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2014
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 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 strengthened the Company's mergers and acquisitions position in the middle market and added 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 $15.0 million of goodwill on the consolidated statements of financial condition, of which $9.1 million is expected to be deductible for income tax purposes. 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 estimated to be $6.0 million and $0.7 million, respectively. 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 statements 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		15,034
	Intangible assets		6,665
	Other assets		7,678
	Total assets acquired		62,712
	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		4,789
	Total liabilities assumed		29,972
	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 on January 1, 2012, the beginning of the prior annual period in which the acquisitions occurred. 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 period 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
	(Dollars in thousands)	September 30, 2013			September 30, 2013
	Net revenues	$	132,773		$	353,728
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,921		$	20,276

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	Discontinued Operations
	The Company's Hong Kong capital markets business ceased operations in 2012. In the second quarter of 2013, the Company completed the sale of FAMCO, an asset management subsidiary, for consideration of $4.0 million which consisted of $0.3 million in cash and a $3.7 million note receivable from the buyer. In accordance with the provisions of ASC 205-20, the results from these businesses have been classified as discontinued operations for all periods presented. The Company recorded a $1.5 million net loss and a $3.9 million net loss from discontinued operations for the three and nine months ended September 30, 2013, respectively.

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, 2014
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)	2014				2013
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	54,386			$	54,097
	Convertible securities	164,580				80,784
	Fixed income securities	41,482				10,102
	Municipal securities:
	Taxable securities	306,534				232,379
	Tax-exempt securities	365,563				460,865
	Short-term securities	78,222				62,620
	Asset-backed securities	99,294				119,811
	U.S. government agency securities	322,284				304,737
	Derivative contracts	51,249				38,633
	Total financial instruments and other inventory positions owned	1,483,594				1,364,028
	Less noncontrolling interests (1)	(234,876		)		(291,513		)
		$	1,248,718			$	1,072,515
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	158,479			$	69,205
	Fixed income securities	23,498				24,021
	U.S. government agency securities	70,992				120,084
	U.S. government securities	505,689				291,320
	Derivative contracts	10,333				8,203
	Total financial instruments and other inventory positions sold, but not yet purchased	768,991				512,833
	Less noncontrolling interests (2)	(113,773		)		(68,356		)
		$	655,218			$	444,477
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $127.4 million and $101.8 million of taxable municipal securities, $102.7 million and $183.9 million of tax-exempt municipal securities, and $4.8 million and $5.8 million of derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
	-2	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $112.5 million and $67.4 million of U.S. government securities, and $1.3 million and $1.0 million of derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
	At September 30, 2014 and December 31, 2013, financial instruments and other inventory positions owned in the amount of $1.0 billion and $957.5 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, treasury futures and exchange traded options.
	Derivative Contract Financial Instruments
	The Company uses interest rate swaps, interest rate locks, credit default swap index contracts, treasury futures and option 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 and option contracts to hedge market value risk associated with its convertible securities and asset-backed 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		2014				2013
	Customer matched-book		Interest rate derivative contract		$	4,917,596			$	5,310,929
	Trading securities		Interest rate derivative contract		307,450				198,500
	Trading securities		Credit default swap index contract		397,815				299,333
	Trading securities		Equity option derivative contract		13,522				17,090
					$	5,636,383			$	5,825,852
	The Company’s derivative contracts do not qualify for hedge accounting, therefore, unrealized gains and losses are recorded on the consolidated statements of operations. The gains and losses on the related economically hedged inventory positions are not disclosed below as they are not in qualifying hedging relationships. 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		2014				2013				2014			2013
	Interest rate derivative contract		Investment banking		$	(809	)		$	(483	)		$	(2,178	)	$	(1,132	)
	Interest rate derivative contract		Institutional brokerage		1,368				(16,532		)		(2,898		)	4,930
	Credit default swap index contract		Institutional brokerage		2,078				(1,918		)		(845		)	(650		)
	Equity option derivative contract		Institutional brokerage		693				—				1,112			—
					$	3,330			$	(18,933	)		$	(4,809	)	$	3,148
	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:
	(Dollars in thousands)				Asset Value at						Liability Value at
					September 30,						September 30,
	Derivative Category		Financial Condition Location		2014				Financial Condition Location		2014
	Interest rate derivative contract		Financial instruments and other inventory positions owned		$	389,825			Financial instruments and other inventory positions sold,  but not yet purchased		$	375,723
	Credit default swap index contract		Financial instruments and other inventory positions owned		7,025				Financial instruments and other inventory positions sold,  but not yet purchased		7,999
	Equity option derivative contract		Financial instruments and other inventory positions owned		63				Financial instruments and other inventory positions sold,  but not yet purchased		247
					$	396,913					$	383,969
	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, 2014, the Company had $25.2 million of uncollateralized credit exposure with these counterparties (notional contract amount of $199.2 million), including $13.3 million of uncollateralized credit exposure with one counterparty.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2014
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 and risk 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 expected 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 11-598 basis points (“bps”) on spreads over U.S. treasury securities, or models based upon prepayment expectations ranging from 102-324 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, treasury futures, options and credit default swap index contracts. These instruments derive their value from underlying assets, reference rates, indices or a combination of these factors. The Company's equity option derivative contracts are valued based on quoted prices from the exchange for identical assets or liabilities as of the period-end date. To the extent these contracts are actively traded and valuation adjustments are not applied, they are categorized as Level I. The Company’s credit default swap index contracts are valued using market price quotations and are classified as Level II. 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 included 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.
	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. 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 (e.g., multiples of revenue and earnings before interest, taxes, depreciation and amortization ("EBITDA")) 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. Merchant banking and other equity investments of $17.9 million and $16.1 million, included within investments on the consolidated statements of financial condition, are accounted for at fair value and are classified as Level III assets at September 30, 2014 and December 31, 2013, respectively. The realized and unrealized gains from fair value changes included in earnings as a result of electing to apply the fair value option to certain financial assets were $2.1 million and $9.5 million for the nine months ended September 30, 2014 and 2013, 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, 2014:
		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 - 6%		3.40%
				Prepayment rates (4)	2 - 22%		4.30%
				Loss severity (3)	25 - 85%		66.00%
				Valuation yields (3)	5 - 10%		5.10%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	3 - 15 bps		11.4 bps
	Investments at fair value:
	Warrants in public and private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 40%		35.50%
	Warrants in private companies	Black-Scholes option pricing model		Stock volatility factors of comparable companies (2)	23 - 94%		47.90%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 6 times		3.6 times
				EBITDA multiple (2)	9 - 12 times		9.4 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)	4 - 40 bps		15.9 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, 2014:
											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	$	46,087		$	8,299		$	—		$	—		$	54,386
	Convertible securities	—			164,580			—			—			164,580
	Fixed income securities	—			41,482			—			—			41,482
	Municipal securities:
	Taxable securities	—			306,534			—			—			306,534
Tax-exempt securities	—			364,257			1,306			—			365,563
Short-term securities	—			77,491			731			—			78,222
Asset-backed securities	—			4,020			95,274			—			99,294
U.S. government agency securities	—			322,284			—			—			322,284
Derivative contracts	63			395,533			1,317			(345,664		)	51,249
Total financial instruments and other inventory positions owned:	46,150			1,684,480			98,628			(345,664		)	1,483,594
Cash equivalents	903			—			—			—			903
Investments at fair value	22,175			—			69,998			—			92,173
Total assets	$	69,228		$	1,684,480		$	168,626		$	(345,664	)	$	1,576,670
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	157,598		$	881		$	—		$	—		$	158,479
Fixed income securities	—			23,498			—			—			23,498
U.S. government agency securities	—			70,992			—			—			70,992
U.S. government securities	505,689			—			—			—			505,689
Derivative contracts	247			373,555			10,167			(373,636		)	10,333
Total financial instruments and other inventory positions sold, but not yet purchased:	$	663,534		$	468,926		$	10,167		$	(373,636	)	$	768,991
-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, 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	$	39,711		$	14,386		$	—		$	—		$	54,097
Convertible securities	—			80,784			—			—			80,784
Fixed income securities	—			10,002			100			—			10,102
Municipal securities:
Taxable securities	—			232,379			—			—			232,379
Tax-exempt securities	—			459,432			1,433			—			460,865
Short-term securities	—			61,964			656			—			62,620
Asset-backed securities	—			12			119,799			—			119,811
U.S. government agency securities	—			304,737			—			—			304,737
Derivative contracts	19			351,589			691			(313,666		)	38,633
Total financial instruments and other inventory positions owned:	39,730			1,515,285			122,679			(313,666		)	1,364,028
Cash equivalents	101,629			—			—			—			101,629
Investments at fair value	20,690			—			49,240			—			69,930
Total assets	$	162,049		$	1,515,285		$	171,919		$	(313,666	)	$	1,535,587
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	69,205		$	—		$	—		$	—		$	69,205
Fixed income securities	—			24,021			—			—			24,021
U.S. government agency securities	—			120,084			—			—			120,084
U.S. government securities	291,320			—			—			—			291,320
Derivative contracts	1,889			324,065			6,643			(324,394		)	8,203
Total financial instruments and other inventory positions sold, but not yet purchased:	$	362,414		$	468,170		$	6,643		$	(324,394	)	$	512,833
-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 $168.6 million and $171.9 million, or 10.7 percent and 11.2 percent of financial instruments measured at fair value at September 30, 2014 and December 31, 2013, respectively. The value of transfers between levels are recognized at the beginning of the reporting period. There were no significant transfers between Level I, Level II or Level III for the nine months ended September 30, 2014.
The following tables summarize the changes in fair value associated with Level III financial instruments held at the beginning or end of the periods presented:
	Balance at															Realized			Unrealized			Balance at
	June 30,									Transfers			Transfers			gains/			gains/			September 30,
(Dollars in thousands)	2014			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2014
Assets:
Financial instruments and other inventory positions owned:
Municipal securities:
Tax-exempt securities	$	1,306		$	—		$	—		$	—		$	—		$	—		$	—		$	1,306
Short-term securities	732			—			—			—			—			—			(1		)	731
Asset-backed securities	129,126			58,028			(93,801		)	515			—			1,377			29			95,274
Derivative contracts	627			—			—			—			—			—			690			1,317
Total financial instruments and other inventory positions owned:	131,791			58,028			(93,801		)	515			—			1,377			718			98,628
Investments at fair value	58,567			10,500			(9		)	—			—			9			931			69,998
Total assets	$	190,358		$	68,528		$	(93,810	)	$	515		$	—		$	1,386		$	1,649		$	168,626
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	10,846		$	(8,439	)	$	—		$	—		$	—		$	8,439		$	(679	)	$	10,167
Total financial instruments and other inventory positions sold, but not yet purchased:	$	10,846		$	(8,439	)	$	—		$	—		$	—		$	8,439		$	(679	)	$	10,167
-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 investment 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)	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 at fair value	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 investment 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)	2013			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2014
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Fixed income securities	$	100		$	—		$	(100	)	$	—		$	—		$	—		$	—		$	—
Municipal securities:
Tax-exempt securities	1,433			—			—			—			—			—			(127		)	1,306
Short-term securities	656			—			(25		)	—			—			6			94			731
Asset-backed securities	119,799			129,764			(163,047		)	—			—			9,748			(990		)	95,274
Derivative contracts	691			2,614			—			—			—			(2,614		)	626			1,317
Total financial instruments and other inventory positions owned:	122,679			132,378			(163,172		)	—			—			7,140			(397		)	98,628
Investments at fair value	49,240			20,500			(2,368		)	—			—			2,368			258			69,998
Total assets	$	171,919		$	152,878		$	(165,540	)	$	—		$	—		$	9,508		$	(139	)	$	168,626
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	6,643		$	(16,751	)	$	—		$	—		$	—		$	16,751		$	3,524		$	10,167
Total financial instruments and other inventory positions sold, but not yet purchased:	$	6,643		$	(16,751	)	$	—		$	—		$	—		$	16,751		$	3,524		$	10,167
-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 investment 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)	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 at fair value	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 investment income/(loss) on the consolidated statements of operations.
The carrying values of the Company’s 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 approximate fair value due to their liquid or short-term nature.

Variable_Interest_Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2014
Variable Interest Entities Disclosure [Abstract]	'
Variable Interest Entities	'
	Variable Interest Entities
	The Company has investments in and/or acts as the managing partner of various partnerships, limited liability companies, or registered mutual funds. 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 or seed investments of the members.
	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 at September 30, 2014 and $0.8 billion at December 31, 2013. The Company’s exposure to loss from these VIEs is $9.7 million, which is the carrying value of its capital contributions recorded in investments on the consolidated statements of financial condition at September 30, 2014. The Company had no liabilities related to these VIEs at September 30, 2014 and December 31, 2013.
	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, 2014.
	The Company has investments in a grantor trust which was established as part of a nonqualified deferred compensation plan. The Company is the primary beneficiary of the grantor trust. Accordingly, the assets and liabilities of the grantor trust are consolidated by the Company on the consolidated statements of financial condition. See Note 20 for additional information on the nonqualified deferred compensation plan.
	The Company also originates CMOs through secondary market vehicles. The Company's risk of loss with respect to these entities is limited to the fair value of the securities held by the Company.

Receivables_from_and_Payables_

Receivables from and Payables to Brokers, Dealers and Clearing Organizations	9 Months Ended
	Sep. 30, 2014
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)	2014		2013
	Receivable arising from unsettled securities transactions	$	156,686	$	59,657
	Deposits paid for securities borrowed	33,310		36,278
	Receivable from clearing organizations	14,419		966
	Deposits with clearing organizations	33,265		20,995
	Securities failed to deliver	17,958		593
	Other	35,552		8,624
		$	291,190	$	127,113
	Amounts payable to brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2014		2013
	Payable arising from unsettled securities transactions	$	63,836	$	5,643
	Payable to clearing organizations	8,590		9,462
	Securities failed to receive	7,101		744
	Other	4,817		11,873
		$	84,344	$	27,722
	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, 2014
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.
	In a reverse repurchase agreement the Company purchases financial instruments from a seller, typically in exchange for cash, and agrees to resell the same or substantially the same financial instruments to the seller at a stated price plus accrued interest in the future. In a repurchase agreement, the Company sells financial instruments to a buyer, typically for cash, and agrees 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 $300.5 million and $212.4 million at September 30, 2014 and December 31, 2013, respectively, of which $292.7 million and $194.9 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 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, 2014:
		Repurchase		Fair Market
	(Dollars in thousands)	Liabilities		Value		Interest Rate
	Term up to 30 day maturities:
	Asset-backed securities	$	11,796	$	16,075	1.75 - 1.84%
	Term of 30 to 90 day maturities:
	Asset-backed securities	4,665		6,218		1.88%
	On demand maturities:
	Corporate securities:
	Fixed income securities	10,907		11,488		0.55%
	U.S. government agency securities	39,605		41,501		0.25 - 0.30%
		$	66,973	$	75,282
	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. There were no gross amounts offset on the consolidated statements of financial condition for reverse repurchase agreements, securities borrowed or repurchase agreements at September 30, 2014 and December 31, 2013, respectively, as a legal right of offset did not exist. The Company had no outstanding securities lending arrangements as of September 30, 2014 or December 31, 2013. See Note 6 for information related to the Company's offsetting of derivative contracts.
	For the nine months ended September 30, 2013, the Company revised its consolidated statements of cash flows to reflect a $36.9 million increase in securities sold under agreements to repurchase from operating activities to financing activities based upon the nature of the repurchase transactions. This change had no effect on net cash for the period presented.

Investments

Investments	9 Months Ended
	Sep. 30, 2014
Investments [Abstract]	'
Investments	'
	Investments
	The Company’s proprietary investments include investments in private companies and partnerships, registered mutual funds, warrants of public and private companies and private company debt. Investments included:
		September 30,			December 31,
	(Dollars in thousands)	2014			2013
	Investments at fair value	$	92,173		$	69,930
	Investments at cost	7,683			20,709
	Investments accounted for under the equity method	25,311			21,404
	Total investments	125,167			112,043
	Less investments attributable to noncontrolling interests (1)	(30,344		)	(21,137		)
		$	94,823		$	90,906
	-1	Noncontrolling interests are attributable to third party ownership in a consolidated merchant banking fund and private equity investment vehicles.
	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, 2014, investments carried on a cost basis had an estimated fair market value of $13.0 million. The estimated fair value of these investments was 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 (e.g., multiples of revenue and EBITDA), and changes in market outlook, among other factors. Because valuation estimates were based upon management’s judgment, 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 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.

Other_Assets

Other Assets	9 Months Ended
	Sep. 30, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Other Assets	'
	Other Assets
	Other assets included:
		September 30,		December 31,
	(Dollars in thousands)	2014		2013
	Net deferred income tax assets	$	37,495	$	36,252
	Fee receivables	24,764		34,415
	Accrued interest receivables	10,856		9,793
	Forgivable loans, net	9,649		7,879
	Prepaid expenses	3,697		5,237
	Other	9,576		8,516
	Total other assets	$	96,037	$	102,092

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2014
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, 2014:
		Capital			Asset
	(Dollars in thousands)	Markets			Management			Total
	Goodwill
	Balance at December 31, 2013	$	13,790		$	196,844		$	210,634
	Goodwill acquired	—			—			—
	Impairment charge	—			—			—
	Measurement period adjustment	1,244			—			1,244
	Balance at September 30, 2014	$	15,034		$	196,844		$	211,878
	Intangible assets
	Balance at December 31, 2013	$	5,316		$	34,614		$	39,930
	Amortization of intangible assets	(2,229		)	(4,725		)	(6,954		)
	Balance at September 30, 2014	$	3,087		$	29,889		$	32,976

ShortTerm_Financing

Short-Term Financing	9 Months Ended
	Sep. 30, 2014
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)	2014		2013		2014		2013
	Commercial paper (secured)	$	247,795	$	280,294	1.51	%	1.59	%
	Prime broker arrangement	—		234,417		N/A		0.9	%
	Bank lines (secured)	91,000		—		1.5	%	N/A
	Total short-term financing	$	338,795	$	514,711
	The Company issues secured commercial paper to fund a portion of its securities inventory. The 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, 2014, the weighted average maturity of CP Series A, CP Series II A and CP Series III A was 140 days, 200 days and 35 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. CP Series III A includes a covenant that requires the Company’s U.S. broker dealer subsidiary to maintain excess net capital of $120 million.
	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 prime broker financing activities are recorded net of receivables from trading activity. The funding is at the discretion of the prime broker subject to a notice period.
	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, 2014 consisted of a one-year $250 million committed revolving credit facility with U.S. Bank, N.A., which was renewed in December 2013. 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 minimum net capital of $120 million, and the unpaid principal amount of all advances under this facility will be due on December 27, 2014. The Company pays a nonrefundable commitment fee on the unused portion of the facility on a quarterly basis. At September 30, 2014, the Company had no advances against this line of credit.
	The Company’s uncommitted secured lines at September 30, 2014 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, 2014, the Company had $91.0 million in advances against these lines of credit.

Variable_Rate_Senior_Notes

Variable Rate Senior Notes	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Variable Rate Senior Notes	'
	Variable Rate Senior Notes
	On November 30, 2012, the Company entered into a 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.
	On June 2, 2014, the Company entered into an amended and restated note purchase agreement ("Amended Note Purchase Agreement") under which the Company issued $50 million of new Class A Notes upon repayment in full of the 2012 Class A Notes. The Class A Notes bear interest at a rate equal to three-month LIBOR plus 3.00 percent and mature on May 31, 2017. The Class B Notes remain outstanding, 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 may not be prepaid by the Company.
	The Amended 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 Amended Note Purchase Agreement proving untrue in any material respect when made by the Company, failure to comply with the covenants in the Amended 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 Amended 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 Amended 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, 2014, the Company was in compliance with all covenants.
	The Notes are recorded at amortized cost. As of September 30, 2014, the carrying value of the Notes approximates fair value.

Contingencies_and_Commitments

Contingencies and Commitments	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Legal Contingencies	'
	Contingencies and Commitments
	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, 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.
	Operating Lease Commitments
	The Company leases office space throughout the United States and in a limited number of foreign countries where the Company’s international operations reside. Aggregate minimum lease commitments under operating leases as of September 30, 2014 are as follows:
	(Dollars in thousands)
	Remainder of 2014	$	2,651
	2015	12,244
	2016	11,901
	2017	9,877
	2018	9,563
	Thereafter	35,441
		$	81,677

Shareholders_Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2014
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. During the nine months ended September 30, 2014, the Company did not repurchase any shares of the Company's outstanding common stock related to 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 251,004 shares or $10.6 million of the Company’s common stock for this purpose during the nine months ended September 30, 2014.
	In the third quarter of 2014, the Company's board of directors authorized the repurchase of up to $100.0 million in common shares through September 30, 2016. This share repurchase authorization became effective on October 1, 2014.
	Issuance of Shares
	During the nine months ended September 30, 2014, the Company issued 103,598 common shares out of treasury stock in fulfillment of $4.2 million in obligations under the Piper Jaffray Companies Retirement Plan (the “Retirement Plan”) and issued 635,347 common shares out of treasury stock as a result of employee restricted share vesting and exercise transactions as discussed in Note 20. 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 Retirement Plan and issued 770,189 common shares out of treasury stock as a result of employee restricted share vesting.

Noncontrolling_Interests

Noncontrolling Interests	9 Months Ended
	Sep. 30, 2014
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 $110.4 million, a merchant banking fund of $22.9 million and private equity investment vehicles aggregating $7.4 million as of September 30, 2014. As of December 31, 2013, noncontrolling interests included the minority equity holders’ proportionate share of the equity in a municipal bond fund of $126.3 million, a merchant banking fund of $14.1 million and private equity investment vehicles aggregating $7.0 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. There was no other comprehensive income or loss attributed to noncontrolling interests for the nine months ended September 30, 2014 and 2013, respectively.
		Common						Total
		Shareholders’			Noncontrolling			Shareholders’
	(Dollars in thousands)	Equity			Interests			Equity
	Balance at December 31, 2013	$	734,676		$	147,396		$	882,072
	Net income	50,629			9,721			60,350
	Amortization/issuance of restricted stock	22,114			—			22,114
	Issuance of treasury shares for options exercised	3,644			—			3,644
	Repurchase of common stock for employee tax withholding	(10,563		)	—			(10,563		)
	Issuance of treasury shares for 401k match	4,156			—			4,156
	Shares reserved/issued for director compensation	120			—			120
	Other comprehensive loss	(143		)	—			(143		)
	Fund capital withdrawals, net	—			(16,402		)	(16,402		)
	Balance at September 30, 2014	$	804,633		$	140,715		$	945,348

Compensation_Plans

Compensation Plans	9 Months Ended
	Sep. 30, 2014
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, 2014:
	Incentive Plan
	Restricted Stock
	Annual grants	811,513
	Sign-on grants	267,651
		1,079,164
	Inducement Plan
	Restricted Stock	29,159
	Total restricted stock related to compensation	1,108,323
	ARI deal consideration (1)	104,496
	Total restricted stock outstanding	1,212,819
	Incentive Plan
	Restricted Stock Units
	Leadership grants	405,826
	Incentive Plan
	Stock options outstanding	261,259
	-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 (1.0 million shares remained available for future issuance under the Incentive Plan as of September 30, 2014). 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’s Annual Grants are made each year in February. 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 2013 for its February 2014 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.
	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.
	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 annual restricted stock units to its leadership team (“Leadership Grants”) beginning in May 2012. 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
	2014		0.82%	41.30%
	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 $7.2 million and $6.0 million for the three months ended September 30, 2014 and 2013, respectively, and $20.5 million and $10.4 million for the nine months ended September 30, 2014 and 2013, 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 Grants, less forfeitures of $0.5 million and $0.1 million for the three months ended September 30, 2014 and 2013, respectively, and $0.6 million and $0.8 million for the nine months ended September 30, 2014 and 2013, respectively. The tax benefit related to stock-based compensation costs totaled $2.8 million and $2.3 million for the three months ended September 30, 2014 and 2013, respectively, and $8.0 million and $4.0 million for the nine months ended September 30, 2014 and 2013, 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, 2014:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2013	1,582,062		$	35.25
	Granted	415,413		40.34
	Vested	(765,283	)	35.17
	Canceled	(19,373	)	36.19
	September 30, 2014	1,212,819		$	37.03
	The following summarizes the changes in the Company’s unvested restricted stock units under the Incentive Plan for the nine months ended September 30, 2014:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2013	290,536		$	15.83
	Granted	115,290		23.42
	Vested	—		—
	Canceled	—		—
	September 30, 2014	405,826		$	17.99
	As of September 30, 2014, there was $11.5 million of total unrecognized compensation cost related to restricted stock and restricted stock units expected to be recognized over a weighted average period of 2.5 years.
	The following table summarizes the changes in the Company’s outstanding stock options for the nine months ended September 30, 2014:
						Weighted Average
			Weighted		Remaining
	Options		Average		Contractual Term	Aggregate
	Outstanding		Exercise Price		(in Years)	Intrinsic Value
December 31, 2013	469,289		$	44.83	2	$	288,318
Granted	—		—
Exercised	(94,478	)	38.57
Canceled	(55	)	39.62
Expired	(113,497	)	47.72
September 30, 2014	261,259		$	45.83	2	$	2,527,750
Options exercisable at September 30, 2014	261,259		$	45.83	2	$	2,527,750
As of September 30, 2014, there was no unrecognized compensation cost related to stock options expected to be recognized over future years.
The intrinsic value of options exercised and the resulting tax benefit realized was $1.1 million and $0.4 million, respectively, for the nine months ended September 30, 2014. There were no options exercised for the nine months ended September 30, 2013.
Deferred Compensation Plans
In 2013, the Company adopted a nonqualified deferred compensation plan, an unfunded plan which allows certain highly compensated employees, at their election, to defer a percentage of their base salary, commissions and/or cash bonuses. The deferrals vest immediately and are non-forfeitable. The amounts deferred under this plan are held in a grantor trust. The Company invests, as a principal, in investments to economically hedge its obligation under the nonqualified deferred compensation plan. Investments in the grantor trust, consisting of mutual funds, totaled $6.5 million as of September 30, 2014, and are included in investments on the consolidated statements of financial condition. The compensation deferred by the employees is expensed in the period earned. The deferred compensation liability was $6.5 million as of September 30, 2014. Changes in the fair value of the investments made by the Company are reported in investment income/(loss) and changes in the corresponding deferred compensation liability are reflected as compensation and benefits expenses on the consolidated statements of operations.
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, 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, 2014
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/(loss) applicable to Piper Jaffray Companies’ common shareholders by the weighted average number of common shares outstanding for the period. Net income/(loss) applicable to Piper Jaffray Companies’ common shareholders represents net income/(loss) 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)	2014			2013			2014			2013
	Net income from continuing operations applicable to Piper Jaffray Companies	$	14,668		$	6,851		$	50,629		$	21,877
	Net loss from discontinued operations	—			(1,529		)	—			(3,921		)
	Net income applicable to Piper Jaffray Companies	14,668			5,322			50,629			17,956
	Earnings allocated to participating securities (1)	(1,116		)	(496		)	(4,243		)	(1,793		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	13,552		$	4,826		$	46,386		$	16,163
	Shares for basic and diluted calculations:
	Average shares used in basic computation	15,066			14,621			14,880			15,271
	Stock options	63			5			54			13
	Average shares used in diluted computation	15,129			14,626			14,934			15,284
	Earnings/(loss) per basic common share:
	Income from continuing operations	$	0.9		$	0.42		$	3.12		$	1.29
	Loss from discontinued operations	—			(0.09		)	—			(0.23		)
	Earnings per basic common share	$	0.9		$	0.33		$	3.12		$	1.06
	Earnings/(loss) per diluted common share:
	Income from continuing operations	$	0.9		$	0.42		$	3.11		$	1.29
	Loss from discontinued operations	—			(0.09		)	—			(0.23		)
	Earnings per diluted common share	$	0.9		$	0.33		$	3.11		$	1.06
	-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 1,245,665 and 1,504,665 for the three months ended September 30, 2014 and 2013, respectively, and 1,366,489 and 1,695,130 for the nine months ended September 30, 2014 and 2013, respectively.
	-2	Net income/(loss) 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, 2014 and 2013.

Segment_Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2014
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)	2014			2013			2014			2013
	Capital Markets
	Investment banking
	Financing
	Equities	$	14,269		$	30,010		$	93,628		$	66,085
	Debt	14,435			12,808			48,148			51,971
	Advisory services	66,320			20,215			145,743			39,165
	Total investment banking	95,024			63,033			287,519			157,221
	Institutional sales and trading
	Equities	16,711			22,958			59,337			65,077
	Fixed income	22,737			17,083			69,060			49,732
	Total institutional sales and trading	39,448			40,041			128,397			114,809
	Management and performance fees	1,387			1,094			4,512			2,677
	Investment income	5,224			7,892			20,600			14,213
	Long-term financing expenses	(1,613		)	(1,797		)	(5,058		)	(5,618		)
	Net revenues	139,470			110,263			435,970			283,302
	Operating expenses (1)	119,001			103,906			364,622			266,301
	Segment pre-tax operating income	$	20,469		$	6,357		$	71,348		$	17,001
	Segment pre-tax operating margin	14.7		%	5.8		%	16.4		%	6		%
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2014			2013			2014			2013
	Asset Management
	Management and performance fees
	Management fees	$	19,738		$	17,547		$	59,474		$	52,191
	Performance fees	470			60			834			716
	Total management and performance fees	20,208			17,607			60,308			52,907
	Investment income/(loss)	(252		)	444			1,312			1,410
	Net revenues	19,956			18,051			61,620			54,317
	Operating expenses (1)	14,733			12,348			44,146			37,757
	Segment pre-tax operating income	$	5,223		$	5,703		$	17,474		$	16,560
	Segment pre-tax operating margin	26.2		%	31.6		%	28.4		%	30.5		%
	Total
	Net revenues	$	159,426		$	128,314		$	497,590		$	337,619
	Operating expenses (1)	133,734			116,254			408,768			304,058
	Pre-tax operating income	$	25,692		$	12,060		$	88,822		$	33,561
	Pre-tax operating margin	16.1		%	9.4		%	17.9		%	9.9		%
	-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)	2014			2013			2014			2013
	Capital Markets	$	743		$	1,238		$	2,229		$	1,238
	Asset Management	1,575			1,661			4,725			4,983
	Total intangible asset amortization expense	$	2,318		$	2,899		$	6,954		$	6,221
	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 location was 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)	2014			2013			2014			2013
	Net revenues:
	United States	$	153,375		$	126,458		$	486,251		$	329,379
	Europe	6,051			1,856			11,339			8,240
	Consolidated	$	159,426		$	128,314		$	497,590		$	337,619
	Long-lived assets are allocated to geographic locations based upon the location of the asset. The following table presents long-lived assets by geographic region:
		September 30,			December 31,
	(Dollars in thousands)	2014			2013
Long-lived assets:
United States	$	293,823		$	296,516
Europe	5,899			6,414
Consolidated	$	299,722		$	302,930

Net_Capital_Requirements_and_O

Net Capital Requirements and Other Regulatory Matters	9 Months Ended
	Sep. 30, 2014
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, 2014, net capital calculated under the SEC rule was $164.2 million, and exceeded the minimum net capital required under the SEC rule by $163.2 million.
	The Company’s committed short-term credit facility and its variable rate senior notes include covenants requiring Piper Jaffray to maintain minimum net capital of $120 million. CP Notes issued under CP Series III A include a covenant that requires Piper Jaffray to maintain excess net capital of $120 million.
	Piper Jaffray Ltd., a 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, 2014, 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, 2014
Income Tax Disclosure [Abstract]	'
Income Tax Disclosure [Text Block]	'
	Income Taxes
	The Company's effective income tax rate from continuing operations, excluding noncontrolling interests, for the three months ended September 30, 2014 was 36.9 percent, compared to 29.6 percent for the three months ended September 30, 2013. For the nine months ended September 30, 2014, the Company's effective income tax rate from continuing operations, excluding noncontrolling interests, was 36.0 percent, compared to 31.6 percent for the nine months ended September 30, 2013. The effective income tax rate for the three and nine months ended September 30, 2013 was unusually low due to the impact of tax-exempt interest income representing a larger proportion of the pre-tax income from continuing operations.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2014
Restructuring [Abstract]	'
Restructuring and Related Activities Disclosure [Text Block]	'
	Restructuring
	For the nine months ended September 30, 2013, the Company incurred pre-tax restructuring charges of $2.9 million from continuing operations. The charges 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.

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2014
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		15,034
	Intangible assets		6,665
	Other assets		7,678
	Total assets acquired		62,712
	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		4,789
	Total liabilities assumed		29,972
	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 period 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
	(Dollars in thousands)	September 30, 2013			September 30, 2013
	Net revenues	$	132,773		$	353,728
	Net income from continuing operations applicable to Piper Jaffray Companies	$	6,921		$	20,276

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, 2014
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)	2014				2013
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	54,386			$	54,097
	Convertible securities	164,580				80,784
	Fixed income securities	41,482				10,102
	Municipal securities:
	Taxable securities	306,534				232,379
	Tax-exempt securities	365,563				460,865
	Short-term securities	78,222				62,620
	Asset-backed securities	99,294				119,811
	U.S. government agency securities	322,284				304,737
	Derivative contracts	51,249				38,633
	Total financial instruments and other inventory positions owned	1,483,594				1,364,028
	Less noncontrolling interests (1)	(234,876		)		(291,513		)
		$	1,248,718			$	1,072,515
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	158,479			$	69,205
	Fixed income securities	23,498				24,021
	U.S. government agency securities	70,992				120,084
	U.S. government securities	505,689				291,320
	Derivative contracts	10,333				8,203
	Total financial instruments and other inventory positions sold, but not yet purchased	768,991				512,833
	Less noncontrolling interests (2)	(113,773		)		(68,356		)
		$	655,218			$	444,477
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $127.4 million and $101.8 million of taxable municipal securities, $102.7 million and $183.9 million of tax-exempt municipal securities, and $4.8 million and $5.8 million of derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
	-2	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $112.5 million and $67.4 million of U.S. government securities, and $1.3 million and $1.0 million of derivative contracts as of September 30, 2014 and December 31, 2013, 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		2014				2013
	Customer matched-book		Interest rate derivative contract		$	4,917,596			$	5,310,929
	Trading securities		Interest rate derivative contract		307,450				198,500
	Trading securities		Credit default swap index contract		397,815				299,333
	Trading securities		Equity option derivative contract		13,522				17,090
					$	5,636,383			$	5,825,852
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		2014				2013				2014			2013
	Interest rate derivative contract		Investment banking		$	(809	)		$	(483	)		$	(2,178	)	$	(1,132	)
	Interest rate derivative contract		Institutional brokerage		1,368				(16,532		)		(2,898		)	4,930
	Credit default swap index contract		Institutional brokerage		2,078				(1,918		)		(845		)	(650		)
	Equity option derivative contract		Institutional brokerage		693				—				1,112			—
					$	3,330			$	(18,933	)		$	(4,809	)	$	3,148
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:
	(Dollars in thousands)				Asset Value at						Liability Value at
					September 30,						September 30,
	Derivative Category		Financial Condition Location		2014				Financial Condition Location		2014
	Interest rate derivative contract		Financial instruments and other inventory positions owned		$	389,825			Financial instruments and other inventory positions sold,  but not yet purchased		$	375,723
	Credit default swap index contract		Financial instruments and other inventory positions owned		7,025				Financial instruments and other inventory positions sold,  but not yet purchased		7,999
	Equity option derivative contract		Financial instruments and other inventory positions owned		63				Financial instruments and other inventory positions sold,  but not yet purchased		247
					$	396,913					$	383,969

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
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, 2014:
		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 - 6%		3.40%
				Prepayment rates (4)	2 - 22%		4.30%
				Loss severity (3)	25 - 85%		66.00%
				Valuation yields (3)	5 - 10%		5.10%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	3 - 15 bps		11.4 bps
	Investments at fair value:
	Warrants in public and private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 40%		35.50%
	Warrants in private companies	Black-Scholes option pricing model		Stock volatility factors of comparable companies (2)	23 - 94%		47.90%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 6 times		3.6 times
				EBITDA multiple (2)	9 - 12 times		9.4 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)	4 - 40 bps		15.9 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, 2014:
											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	$	46,087		$	8,299		$	—		$	—		$	54,386
	Convertible securities	—			164,580			—			—			164,580
	Fixed income securities	—			41,482			—			—			41,482
	Municipal securities:
	Taxable securities	—			306,534			—			—			306,534
	Tax-exempt securities	—			364,257			1,306			—			365,563
	Short-term securities	—			77,491			731			—			78,222
	Asset-backed securities	—			4,020			95,274			—			99,294
	U.S. government agency securities	—			322,284			—			—			322,284
	Derivative contracts	63			395,533			1,317			(345,664		)	51,249
	Total financial instruments and other inventory positions owned:	46,150			1,684,480			98,628			(345,664		)	1,483,594
	Cash equivalents	903			—			—			—			903
	Investments at fair value	22,175			—			69,998			—			92,173
	Total assets	$	69,228		$	1,684,480		$	168,626		$	(345,664	)	$	1,576,670
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	157,598		$	881		$	—		$	—		$	158,479
	Fixed income securities	—			23,498			—			—			23,498
	U.S. government agency securities	—			70,992			—			—			70,992
	U.S. government securities	505,689			—			—			—			505,689
	Derivative contracts	247			373,555			10,167			(373,636		)	10,333
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	663,534		$	468,926		$	10,167		$	(373,636	)	$	768,991
	-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, 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	$	39,711		$	14,386		$	—		$	—		$	54,097
	Convertible securities	—			80,784			—			—			80,784
	Fixed income securities	—			10,002			100			—			10,102
	Municipal securities:
	Taxable securities	—			232,379			—			—			232,379
	Tax-exempt securities	—			459,432			1,433			—			460,865
	Short-term securities	—			61,964			656			—			62,620
	Asset-backed securities	—			12			119,799			—			119,811
	U.S. government agency securities	—			304,737			—			—			304,737
	Derivative contracts	19			351,589			691			(313,666		)	38,633
	Total financial instruments and other inventory positions owned:	39,730			1,515,285			122,679			(313,666		)	1,364,028
	Cash equivalents	101,629			—			—			—			101,629
	Investments at fair value	20,690			—			49,240			—			69,930
	Total assets	$	162,049		$	1,515,285		$	171,919		$	(313,666	)	$	1,535,587
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	69,205		$	—		$	—		$	—		$	69,205
	Fixed income securities	—			24,021			—			—			24,021
	U.S. government agency securities	—			120,084			—			—			120,084
	U.S. government securities	291,320			—			—			—			291,320
	Derivative contracts	1,889			324,065			6,643			(324,394		)	8,203
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	362,414		$	468,170		$	6,643		$	(324,394	)	$	512,833
-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 held at the beginning or end of the periods presented:
		Balance at															Realized			Unrealized			Balance at
		June 30,									Transfers			Transfers			gains/			gains/			September 30,
	(Dollars in thousands)	2014			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2014
	Assets:
	Financial instruments and other inventory positions owned:
	Municipal securities:
	Tax-exempt securities	$	1,306		$	—		$	—		$	—		$	—		$	—		$	—		$	1,306
	Short-term securities	732			—			—			—			—			—			(1		)	731
	Asset-backed securities	129,126			58,028			(93,801		)	515			—			1,377			29			95,274
	Derivative contracts	627			—			—			—			—			—			690			1,317
	Total financial instruments and other inventory positions owned:	131,791			58,028			(93,801		)	515			—			1,377			718			98,628
	Investments at fair value	58,567			10,500			(9		)	—			—			9			931			69,998
	Total assets	$	190,358		$	68,528		$	(93,810	)	$	515		$	—		$	1,386		$	1,649		$	168,626
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts	$	10,846		$	(8,439	)	$	—		$	—		$	—		$	8,439		$	(679	)	$	10,167
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	10,846		$	(8,439	)	$	—		$	—		$	—		$	8,439		$	(679	)	$	10,167
	-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 investment 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)	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 at fair value	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 investment 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)	2013			Purchases			Sales			in			out			(losses) (1)			(losses) (1)			2014
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Fixed income securities	$	100		$	—		$	(100	)	$	—		$	—		$	—		$	—		$	—
	Municipal securities:
	Tax-exempt securities	1,433			—			—			—			—			—			(127		)	1,306
	Short-term securities	656			—			(25		)	—			—			6			94			731
	Asset-backed securities	119,799			129,764			(163,047		)	—			—			9,748			(990		)	95,274
	Derivative contracts	691			2,614			—			—			—			(2,614		)	626			1,317
	Total financial instruments and other inventory positions owned:	122,679			132,378			(163,172		)	—			—			7,140			(397		)	98,628
	Investments at fair value	49,240			20,500			(2,368		)	—			—			2,368			258			69,998
	Total assets	$	171,919		$	152,878		$	(165,540	)	$	—		$	—		$	9,508		$	(139	)	$	168,626
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts	$	6,643		$	(16,751	)	$	—		$	—		$	—		$	16,751		$	3,524		$	10,167
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	6,643		$	(16,751	)	$	—		$	—		$	—		$	16,751		$	3,524		$	10,167
	-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 investment 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)	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 at fair value	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 investment 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, 2014
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)	2014		2013
	Receivable arising from unsettled securities transactions	$	156,686	$	59,657
	Deposits paid for securities borrowed	33,310		36,278
	Receivable from clearing organizations	14,419		966
	Deposits with clearing organizations	33,265		20,995
	Securities failed to deliver	17,958		593
	Other	35,552		8,624
		$	291,190	$	127,113
	Amounts payable to brokers, dealers and clearing organizations included:
		September 30,		December 31,
	(Dollars in thousands)	2014		2013
	Payable arising from unsettled securities transactions	$	63,836	$	5,643
	Payable to clearing organizations	8,590		9,462
	Securities failed to receive	7,101		744
	Other	4,817		11,873
		$	84,344	$	27,722

Collateralized_Securities_Tran1

Collateralized Securities Transactions (Tables)	9 Months Ended
	Sep. 30, 2014
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 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, 2014:
		Repurchase		Fair Market
	(Dollars in thousands)	Liabilities		Value		Interest Rate
	Term up to 30 day maturities:
	Asset-backed securities	$	11,796	$	16,075	1.75 - 1.84%
	Term of 30 to 90 day maturities:
	Asset-backed securities	4,665		6,218		1.88%
	On demand maturities:
	Corporate securities:
	Fixed income securities	10,907		11,488		0.55%
	U.S. government agency securities	39,605		41,501		0.25 - 0.30%
		$	66,973	$	75,282

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2014
Investments [Abstract]	'
Schedule of Investments	'
	The Company’s proprietary investments include investments in private companies and partnerships, registered mutual funds, warrants of public and private companies and private company debt. Investments included:
		September 30,			December 31,
	(Dollars in thousands)	2014			2013
	Investments at fair value	$	92,173		$	69,930
	Investments at cost	7,683			20,709
	Investments accounted for under the equity method	25,311			21,404
	Total investments	125,167			112,043
	Less investments attributable to noncontrolling interests (1)	(30,344		)	(21,137		)
		$	94,823		$	90,906
	-1	Noncontrolling interests are attributable to third party ownership in a consolidated merchant banking fund and private equity investment vehicles.

Other_Assets_Tables

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Other Assets	'
	Other assets included:
		September 30,		December 31,
	(Dollars in thousands)	2014		2013
	Net deferred income tax assets	$	37,495	$	36,252
	Fee receivables	24,764		34,415
	Accrued interest receivables	10,856		9,793
	Forgivable loans, net	9,649		7,879
	Prepaid expenses	3,697		5,237
	Other	9,576		8,516
	Total other assets	$	96,037	$	102,092

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2014
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, 2014:
		Capital			Asset
	(Dollars in thousands)	Markets			Management			Total
	Goodwill
	Balance at December 31, 2013	$	13,790		$	196,844		$	210,634
	Goodwill acquired	—			—			—
	Impairment charge	—			—			—
	Measurement period adjustment	1,244			—			1,244
	Balance at September 30, 2014	$	15,034		$	196,844		$	211,878
	Intangible assets
	Balance at December 31, 2013	$	5,316		$	34,614		$	39,930
	Amortization of intangible assets	(2,229		)	(4,725		)	(6,954		)
	Balance at September 30, 2014	$	3,087		$	29,889		$	32,976

ShortTerm_Financing_Tables

Short-Term Financing (Tables)	9 Months Ended
	Sep. 30, 2014
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)	2014		2013		2014		2013
	Commercial paper (secured)	$	247,795	$	280,294	1.51	%	1.59	%
	Prime broker arrangement	—		234,417		N/A		0.9	%
	Bank lines (secured)	91,000		—		1.5	%	N/A
	Total short-term financing	$	338,795	$	514,711

Contingencies_and_Commitments_

Contingencies and Commitments (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	'
	The Company leases office space throughout the United States and in a limited number of foreign countries where the Company’s international operations reside. Aggregate minimum lease commitments under operating leases as of September 30, 2014 are as follows:
	(Dollars in thousands)
	Remainder of 2014	$	2,651
	2015	12,244
	2016	11,901
	2017	9,877
	2018	9,563
	Thereafter	35,441
		$	81,677

Noncontrolling_Interests_Table

Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2014
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, 2013	$	734,676		$	147,396		$	882,072
	Net income	50,629			9,721			60,350
	Amortization/issuance of restricted stock	22,114			—			22,114
	Issuance of treasury shares for options exercised	3,644			—			3,644
	Repurchase of common stock for employee tax withholding	(10,563		)	—			(10,563		)
	Issuance of treasury shares for 401k match	4,156			—			4,156
	Shares reserved/issued for director compensation	120			—			120
	Other comprehensive loss	(143		)	—			(143		)
	Fund capital withdrawals, net	—			(16,402		)	(16,402		)
	Balance at September 30, 2014	$	804,633		$	140,715		$	945,348

Compensation_Plans_Tables

Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2014
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, 2014:
	Incentive Plan
	Restricted Stock
	Annual grants	811,513
	Sign-on grants	267,651
		1,079,164
	Inducement Plan
	Restricted Stock	29,159
	Total restricted stock related to compensation	1,108,323
	ARI deal consideration (1)	104,496
	Total restricted stock outstanding	1,212,819
	Incentive Plan
	Restricted Stock Units
	Leadership grants	405,826
	Incentive Plan
	Stock options outstanding	261,259
	-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
	2014		0.82%	41.30%
	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, 2014:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2013	1,582,062		$	35.25
	Granted	415,413		40.34
	Vested	(765,283	)	35.17
	Canceled	(19,373	)	36.19
	September 30, 2014	1,212,819		$	37.03
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, 2014:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2013	290,536		$	15.83
	Granted	115,290		23.42
	Vested	—		—
	Canceled	—		—
	September 30, 2014	405,826		$	17.99
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, 2014:
						Weighted Average
				Weighted		Remaining
		Options		Average		Contractual Term	Aggregate
		Outstanding		Exercise Price		(in Years)	Intrinsic Value
	December 31, 2013	469,289		$	44.83	2	$	288,318
	Granted	—		—
	Exercised	(94,478	)	38.57
	Canceled	(55	)	39.62
	Expired	(113,497	)	47.72
	September 30, 2014	261,259		$	45.83	2	$	2,527,750
	Options exercisable at September 30, 2014	261,259		$	45.83	2	$	2,527,750

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
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)	2014			2013			2014			2013
	Net income from continuing operations applicable to Piper Jaffray Companies	$	14,668		$	6,851		$	50,629		$	21,877
	Net loss from discontinued operations	—			(1,529		)	—			(3,921		)
	Net income applicable to Piper Jaffray Companies	14,668			5,322			50,629			17,956
	Earnings allocated to participating securities (1)	(1,116		)	(496		)	(4,243		)	(1,793		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	13,552		$	4,826		$	46,386		$	16,163
	Shares for basic and diluted calculations:
	Average shares used in basic computation	15,066			14,621			14,880			15,271
	Stock options	63			5			54			13
	Average shares used in diluted computation	15,129			14,626			14,934			15,284
	Earnings/(loss) per basic common share:
	Income from continuing operations	$	0.9		$	0.42		$	3.12		$	1.29
	Loss from discontinued operations	—			(0.09		)	—			(0.23		)
	Earnings per basic common share	$	0.9		$	0.33		$	3.12		$	1.06
	Earnings/(loss) per diluted common share:
	Income from continuing operations	$	0.9		$	0.42		$	3.11		$	1.29
	Loss from discontinued operations	—			(0.09		)	—			(0.23		)
	Earnings per diluted common share	$	0.9		$	0.33		$	3.11		$	1.06
	-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 1,245,665 and 1,504,665 for the three months ended September 30, 2014 and 2013, respectively, and 1,366,489 and 1,695,130 for the nine months ended September 30, 2014 and 2013, respectively.
	-2	Net income/(loss) 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, 2014
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)	2014			2013			2014			2013
	Capital Markets
	Investment banking
	Financing
	Equities	$	14,269		$	30,010		$	93,628		$	66,085
	Debt	14,435			12,808			48,148			51,971
	Advisory services	66,320			20,215			145,743			39,165
	Total investment banking	95,024			63,033			287,519			157,221
	Institutional sales and trading
	Equities	16,711			22,958			59,337			65,077
	Fixed income	22,737			17,083			69,060			49,732
	Total institutional sales and trading	39,448			40,041			128,397			114,809
	Management and performance fees	1,387			1,094			4,512			2,677
	Investment income	5,224			7,892			20,600			14,213
	Long-term financing expenses	(1,613		)	(1,797		)	(5,058		)	(5,618		)
	Net revenues	139,470			110,263			435,970			283,302
	Operating expenses (1)	119,001			103,906			364,622			266,301
	Segment pre-tax operating income	$	20,469		$	6,357		$	71,348		$	17,001
	Segment pre-tax operating margin	14.7		%	5.8		%	16.4		%	6		%
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2014			2013			2014			2013
	Asset Management
	Management and performance fees
	Management fees	$	19,738		$	17,547		$	59,474		$	52,191
	Performance fees	470			60			834			716
	Total management and performance fees	20,208			17,607			60,308			52,907
	Investment income/(loss)	(252		)	444			1,312			1,410
	Net revenues	19,956			18,051			61,620			54,317
	Operating expenses (1)	14,733			12,348			44,146			37,757
	Segment pre-tax operating income	$	5,223		$	5,703		$	17,474		$	16,560
	Segment pre-tax operating margin	26.2		%	31.6		%	28.4		%	30.5		%
	Total
	Net revenues	$	159,426		$	128,314		$	497,590		$	337,619
	Operating expenses (1)	133,734			116,254			408,768			304,058
	Pre-tax operating income	$	25,692		$	12,060		$	88,822		$	33,561
	Pre-tax operating margin	16.1		%	9.4		%	17.9		%	9.9		%
	-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)	2014			2013			2014			2013
	Capital Markets	$	743		$	1,238		$	2,229		$	1,238
	Asset Management	1,575			1,661			4,725			4,983
	Total intangible asset amortization expense	$	2,318		$	2,899		$	6,954		$	6,221
Schedule of Intangible Asset Amortization Expense	'
	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)	2014			2013			2014			2013
	Capital Markets	$	743		$	1,238		$	2,229		$	1,238
	Asset Management	1,575			1,661			4,725			4,983
	Total intangible asset amortization expense	$	2,318		$	2,899		$	6,954		$	6,221
Net Revenues by Geographic Locations	'
	Net revenues exclude discontinued operations for all periods presented.
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(Dollars in thousands)	2014			2013			2014			2013
	Net revenues:
	United States	$	153,375		$	126,458		$	486,251		$	329,379
	Europe	6,051			1,856			11,339			8,240
	Consolidated	$	159,426		$	128,314		$	497,590		$	337,619
Long-Lived Assets by Geographic Region	'
	Long-lived assets are allocated to geographic locations based upon the location of the asset. The following table presents long-lived assets by geographic region:
		September 30,			December 31,
	(Dollars in thousands)	2014			2013
	Long-lived assets:
	United States	$	293,823		$	296,516
	Europe	5,899			6,414
	Consolidated	$	299,722		$	302,930

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail) (USD $)	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	segment	Interest Revenue [Member]	Interest Revenue [Member]	Interest Expense [Member]	Interest Expense [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]	'	'	'	'	'
Number of reportable segments	2	'	'	'	'
Reclassified amount	'	$3.90	$8.50	$4.30	$9.80

Acquisitions_Additional_Inform

Acquisitions - Additional Information(Details) (USD $)	0 Months Ended	9 Months Ended
	Jul. 16, 2013	Sep. 30, 2014
Business Acquisition [Line Items]	'	'
Goodwill acquired	'	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.	'	'
Business Acquisition [Line Items]	'	'
Consideration transferred	32,740,000	'
Acquisition related compensation arrangements	14,300,000	'
Goodwill acquired	15,034,000	'
Goodwill amount expected to be deducted for income tax purposes	9,100,000	'
Intangible assets	6,665,000	'
Business Combination, Acquisition Related Costs	'	900,000
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. | Customer Relationships	'	'
Business Acquisition [Line Items]	'	'
Intangible assets	6,000,000	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. | Noncompete Agreements	'	'
Business Acquisition [Line Items]	'	'
Intangible assets	$700,000	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. | Minimum [Member]	'	'
Business Acquisition [Line Items]	'	'
Acquisition related compensation arrangement award vesting period	'2 years	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. | Maximum	'	'
Business Acquisition [Line Items]	'	'
Acquisition related compensation arrangement award vesting period	'5 years	'
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. | Weighted Average	'	'
Business Acquisition [Line Items]	'	'
Acquisition related compensation arrangement award vesting period	'4 years 3 months	'

Acquisitions_Estimated_Fair_Va

Acquisitions - Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Jul. 16, 2013
In Thousands, unless otherwise specified			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	211,878	210,634	15,034
Intangible assets	'	'	6,665
Other assets	'	'	7,678
Total assets acquired	'	'	62,712
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	'	'	4,789
Total liabilities assumed	'	'	29,972
Net assets acquired	'	'	$32,740

Acquisitions_Unaudited_Pro_For

Acquisitions - Unaudited Pro Forma Information (Details) (Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. [Member], USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013
Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. [Member]	'	'
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'	'
Net revenues	$132,773	$353,728
Net income from continuing operations applicable to Piper Jaffray Companies	$6,921	$20,276

Discontinued_Operations_Detail

Discontinued Operations (Details Textual) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Loss from discontinued operations, net of tax	$0	($1,529,000)	$0	($3,921,000)
FAMCO	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Sale of FAMCO, sale price	'	4,000,000	'	4,000,000
Sale of FAMCO, cash proceeds	'	300,000	'	'
Sale of FAMCO, note receivable received	'	$3,700,000	'	'

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, 2014	Dec. 31, 2013
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	$1,483,594	$1,364,028
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-234,876	-291,513
Financial instruments and other inventory positions owned, attributable to parent	1,248,718	1,072,515
Financial instruments and other inventory positions sold, but not yet purchased	768,991	512,833
Financial instruments and other inventory positions owned and pledged as collateral	1,023,970	957,515
Fair Value, Disclosure Item Amounts [Domain]	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Financial instruments and other inventory positions owned and pledged as collateral, attributable to parent	655,218	444,477
Equity securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	54,386	54,097
Financial instruments and other inventory positions sold, but not yet purchased	158,479	69,205
Convertible securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	164,580	80,784
Fixed income securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	41,482	10,102
Financial instruments and other inventory positions sold, but not yet purchased	23,498	24,021
Taxable securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	306,534	232,379
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-127,400	-101,800
Tax-exempt securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	365,563	460,865
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-102,700	-183,900
Short-term securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	78,222	62,620
Asset-backed securities	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	99,294	119,811
US Government Corporations and Agencies Securities [Member]	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	322,284	304,737
Financial instruments and other inventory positions sold, but not yet purchased	70,992	120,084
US Treasury Securities [Member]	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Financial instruments and other inventory positions sold, but not yet purchased	505,689	291,320
Financial instruments and other inventory positions owned and pledged as collateral, attributable to noncontrolling interest	-112,500	-67,400
Derivative contracts	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Total financial instruments and other inventory positions owned	51,249	38,633
Financial instruments and other inventory positions owned, attributable to noncontrolling interest	-4,800	-5,800
Financial instruments and other inventory positions sold, but not yet purchased	10,333	8,203
Financial instruments and other inventory positions owned and pledged as collateral, attributable to noncontrolling interest	-1,300	-1,000
Non-Controlling interests financial instruments [Member]	'	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'	'
Financial instruments and other inventory positions owned and pledged as collateral, attributable to noncontrolling interest	($113,773)	($68,356)

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, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	$5,636,383	$5,825,852
Customer matched-book | Interest rate derivative contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	4,917,596	5,310,929
Trading Securities [Member] | Interest rate derivative contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	307,450	198,500
Trading Securities [Member] | Credit default swap index contract	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	397,815	299,333
Trading Securities [Member] | Equity Option [Member]	'	'
Derivative [Line Items]	'	'
Absolute Notional Contract Amount of Derivative Instruments	$13,522	$17,090

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	$3,330	($18,933)	($4,809)	$3,148
Interest rate derivative contract | Investment banking	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	-809	-483	-2,178	-1,132
Interest rate derivative contract | Institutional brokerage	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	1,368	-16,532	-2,898	4,930
Credit default swap index contract | Institutional brokerage	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	2,078	-1,918	-845	-650
Equity Option Derivative Contract [Member] | Institutional brokerage	'	'	'	'
Derivative [Line Items]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Instruments	$693	$0	$1,112	$0

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, 2014
In Thousands, unless otherwise specified
Derivative [Line Items]	'
Fair value of derivative assets, gross	$396,913
Fair value of derivative liabilities, gross	383,969
Financial instruments and other inventory positions owned | Interest rate derivative contract	'
Derivative [Line Items]	'
Fair value of derivative assets, gross	389,825
Financial instruments and other inventory positions owned | Credit default swap index contract	'
Derivative [Line Items]	'
Fair value of derivative assets, gross	7,025
Financial instruments and other inventory positions owned | Equity Option [Member]	'
Derivative [Line Items]	'
Fair value of derivative assets, gross	63
Financial instruments and other inventory positions sold, but not yet purchased | Interest rate derivative contract	'
Derivative [Line Items]	'
Fair value of derivative liabilities, gross	375,723
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	7,999
Financial instruments and other inventory positions sold, but not yet purchased | Equity Option [Member]	'
Derivative [Line Items]	'
Fair value of derivative liabilities, gross	$247

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, 2014
In Millions, unless otherwise specified
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'
Uncollateralized credit exposure	$25.20
Notional contract amount of derivatives with counterparties not required to post collateral	199.2
Counterparty	'
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]	'
Uncollateralized credit exposure	$13.30

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Investments at fair value	$92,173,000	'	$92,173,000	'	$69,930,000
Gains from fair value changes	'	'	2,100,000	9,500,000	'
Total assets	1,576,670,000	'	1,576,670,000	'	1,535,587,000
Transfers of financial assets from Level III	'	870,000	'	619,000	'
Goodwill impairment	'	'	'	'	'
Transfers between fair value levels	'	'	0	'	'
Level III	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Investments at fair value	69,998,000	'	69,998,000	'	49,240,000
Total assets	168,626,000	'	168,626,000	'	171,919,000
Percentage of Level III assets to financial instruments measured at fair value	10.70%	'	10.70%	'	11.20%
Minimum | U.S. government agency securities	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Market yields basis points spreads to treasury securities (as a percent)	0.11%	'	0.11%	'	'
Prepayment expectations based upon PSA prepayment levels	102	'	102	'	'
Maximum | U.S. government agency securities	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Market yields basis points spreads to treasury securities (as a percent)	5.98%	'	5.98%	'	'
Prepayment expectations based upon PSA prepayment levels	324	'	324	'	'
Merchant Banking Investments | Merchant Banking Investments	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Investments at fair value	$17,900,000	'	$17,900,000	'	$16,100,000

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Information about Significant Unobservable Inputs used in Fair Value Measurement (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$168,626	$212,881	$168,626	$212,881	$190,358	$171,919	$226,339	$152,328
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	68,528	99,763	152,878	464,349	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	93,810	121,554	165,540	447,948	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	515	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	870	'	619	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	1,386	18,842	9,508	38,765	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	1,649	-9,639	-139	6,006	'	'	'	'
Minimum [Member]	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	'	'	8.7	'	'	'	'	'
Minimum [Member] | U.S. government agency securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Market Yields Basis Point	0.11%	'	0.11%	'	'	'	'	'
Maximum	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	'	'	12	'	'	'	'	'
Maximum | U.S. government agency securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Market Yields Basis Point	5.98%	'	5.98%	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased | Minimum [Member] | Discounted cash flow | Level III | Interest rate derivative contract	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Unamortized premium over the MMD curve	'	'	0.04%	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased | Maximum | Discounted cash flow | Level III | Interest rate derivative contract	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Unamortized premium over the MMD curve	'	'	0.40%	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased | Weighted Average | Discounted cash flow | Level III | Interest rate derivative contract	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Unamortized premium over the MMD curve	'	'	0.16%	'	'	'	'	'
Financial instruments and other inventory positions owned	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	98,628	167,302	98,628	167,302	131,791	122,679	172,772	119,083
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	58,028	99,763	132,378	448,986	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	93,801	111,198	163,172	437,592	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	515	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	251	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	1,377	12,900	7,140	32,819	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	718	-6,684	-397	4,006	'	'	'	'
Financial instruments and other inventory positions owned | Convertible securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	0	'	0	'	'	1,308	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	0	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	1,615	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	'	0	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	251	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	'	839	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	'	-281	'	'	'	'	'	'
Financial instruments and other inventory positions owned | Tax-exempt securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1,306	1,433	1,306	1,433	1,306	1,433	1,433	1,429
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	'	1	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	'	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	'	'	'	-266	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	'	'	-127	269	'	'	'	'
Financial instruments and other inventory positions owned | Short-term securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	731	656	731	656	732	656	656	656
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	'	25	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	'	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	'	'	6	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	-1	'	94	'	'	'	'	'
Financial instruments and other inventory positions owned | Asset-backed securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	95,274	157,042	95,274	157,042	129,126	119,799	151,396	116,171
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	58,028	99,763	129,764	448,175	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	93,801	97,246	163,047	424,274	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	515	'	'	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	'	'	'	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Realized Gain Loss Included In Earnings	1,377	-276	9,748	20,562	'	'	'	'
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Unrealized Gain Loss Included In Earnings	$29	$3,405	($990)	($3,592)	'	'	'	'
Financial instruments and other inventory positions owned | Minimum [Member] | Discounted cash flow | Level III | 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 [Member] | Discounted cash flow | Level III | 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 [Member] | Discounted cash flow | Level III | Collateralized by Residential mortgages	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Credit default rate	'	'	0.50%	'	'	'	'	'
Prepayment rates	'	'	2.00%	'	'	'	'	'
Loss severity	'	'	25.00%	'	'	'	'	'
Valuation yields	'	'	5.00%	'	'	'	'	'
Financial instruments and other inventory positions owned | Minimum [Member] | Discounted cash flow | Level III | Interest rate derivative contract	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Unamortized premium over the MMD curve	'	'	0.03%	'	'	'	'	'
Financial instruments and other inventory positions owned | Minimum [Member] | Black-Scholes option pricing model | Level III | 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 [Member] | Black-Scholes option pricing model | Level III | Warrants in private companies	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Stock volatility factors of comparable companies	'	'	23.27%	'	'	'	'	'
Financial instruments and other inventory positions owned | Minimum [Member] | Market Comparable | Level III | 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 | Maximum | Discounted cash flow | Level III | 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 | Level III | 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 | Level III | Collateralized by Residential mortgages	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Credit default rate	'	'	6.00%	'	'	'	'	'
Prepayment rates	'	'	22.00%	'	'	'	'	'
Loss severity	'	'	85.00%	'	'	'	'	'
Valuation yields	'	'	10.00%	'	'	'	'	'
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Level III | Interest rate derivative contract	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Unamortized premium over the MMD curve	'	'	0.15%	'	'	'	'	'
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Level III | Equity investment in private company	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Revenue multiple	'	'	6.1	'	'	'	'	'
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Level III | Warrants in public and private companies	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Liquidity discount rates	'	'	40.00%	'	'	'	'	'
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Level III | Warrants in private companies	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Stock volatility factors of comparable companies	'	'	93.60%	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Level III | Tax-exempt securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Debt service coverage ratio	'	'	22.20%	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Level III | Short-term securities	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Expected recovery rate (% of par)	'	'	79.60%	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Level III | Collateralized by Residential mortgages	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Credit default rate	'	'	3.36%	'	'	'	'	'
Prepayment rates	'	'	4.28%	'	'	'	'	'
Loss severity	'	'	66.03%	'	'	'	'	'
Valuation yields	'	'	5.06%	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Level III | 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 | Level III | Equity investment in private company	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Revenue multiple	'	'	3.6	'	'	'	'	'
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	'	'	9.4	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Level III | Warrants in public and private companies	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Liquidity discount rates	'	'	35.50%	'	'	'	'	'
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Level III | Warrants in private companies	'	'	'	'	'	'	'	'
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]	'	'	'	'	'	'	'	'
Stock volatility factors of comparable companies	'	'	47.90%	'	'	'	'	'

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Valuation of Financial Instruments by Pricing Observability Levels (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	$1,483,594	'	$1,364,028	'	'	'
Cash equivalents	903	'	101,629	'	'	'
Investments at fair value	92,173	'	69,930	'	'	'
Total assets	1,576,670	'	1,535,587	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	768,991	'	512,833	'	'	'
Equity securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	54,386	'	54,097	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	158,479	'	69,205	'	'	'
Convertible securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	164,580	'	80,784	'	'	'
Fixed income securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	41,482	'	10,102	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	23,498	'	24,021	'	'	'
Taxable securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	306,534	'	232,379	'	'	'
Tax-exempt securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	365,563	'	460,865	'	'	'
Short-term securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	78,222	'	62,620	'	'	'
Asset-backed securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	99,294	'	119,811	'	'	'
U.S. government agency securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	322,284	'	304,737	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	70,992	'	120,084	'	'	'
U.S. government securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	505,689	'	291,320	'	'	'
Derivative contracts	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	51,249	'	38,633	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	10,333	'	8,203	'	'	'
Level I	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	46,150	'	39,730	'	'	'
Cash equivalents	903	'	101,629	'	'	'
Investments at fair value	22,175	'	20,690	'	'	'
Total assets	69,228	'	162,049	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	663,534	'	362,414	'	'	'
Level I | Equity securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	46,087	'	39,711	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	157,598	'	69,205	'	'	'
Level I | Convertible securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level I | Fixed income securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total 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]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level I | Tax-exempt securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level I | Short-term securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level I | Asset-backed securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level I | U.S. government agency securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total 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 sold, but not yet purchased	505,689	'	291,320	'	'	'
Level I | Derivative contracts	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	63	'	19	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	247	'	1,889	'	'	'
Level II	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	1,684,480	'	1,515,285	'	'	'
Cash equivalents	'	'	'	'	'	'
Investments at fair value	'	'	'	'	'	'
Total assets	1,684,480	'	1,515,285	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	468,926	'	468,170	'	'	'
Level II | Equity securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	8,299	'	14,386	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	881	'	'	'	'	'
Level II | Convertible securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	164,580	'	80,784	'	'	'
Level II | Fixed income securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	41,482	'	10,002	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	23,498	'	24,021	'	'	'
Level II | Taxable securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	306,534	'	232,379	'	'	'
Level II | Tax-exempt securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	364,257	'	459,432	'	'	'
Level II | Short-term securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	77,491	'	61,964	'	'	'
Level II | Asset-backed securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	4,020	'	12	'	'	'
Level II | U.S. government agency securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	322,284	'	304,737	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	70,992	'	120,084	'	'	'
Level II | U.S. government securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
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]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	395,533	'	351,589	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	373,555	'	324,065	'	'	'
Level III	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	98,628	'	122,679	'	'	'
Cash equivalents	'	'	'	'	'	'
Investments at fair value	69,998	'	49,240	'	'	'
Total assets	168,626	'	171,919	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	10,167	'	6,643	'	'	'
Level III | Equity securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total 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]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level III | Fixed income securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total 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]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Level III | Tax-exempt securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	1,306	'	1,433	'	'	'
Level III | Short-term securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	731	'	656	'	'	'
Level III | Asset-backed securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	95,274	'	119,799	'	'	'
Level III | U.S. government agency securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total 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 sold, but not yet purchased	'	'	'	'	'	'
Level III | Derivative contracts	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	1,317	'	691	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	10,167	'	6,643	'	'	'
Counterparty and Cash Collateral Netting	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	-345,664	'	-313,666	'	'	'
Cash equivalents	'	'	'	'	'	'
Investments at fair value	'	'	'	'	'	'
Total assets	-345,664	'	-313,666	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	-373,636	'	-324,394	'	'	'
Counterparty and Cash Collateral Netting | Equity securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Convertible securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Fixed income securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Taxable securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Tax-exempt securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Short-term securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Asset-backed securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | U.S. government agency securities	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	'	'	'	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	'	'	'	'	'	'
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 sold, but not yet purchased	'	'	'	'	'	'
Counterparty and Cash Collateral Netting | Derivative contracts	'	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Total financial instruments and other inventory positions owned	-345,664	'	-313,666	'	'	'
Financial instruments and other inventory positions sold, but not yet purchased	-373,636	'	-324,394	'	'	'
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	10,167	10,846	6,643	6,581	254	5,218
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	$10,167	$10,846	$6,643	$6,581	$254	$5,218

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
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Transfers between fair value levels	'	'	$0	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	190,358,000	226,339,000	171,919,000	152,328,000
Purchases	68,528,000	99,763,000	152,878,000	464,349,000
Sales	-93,810,000	-121,554,000	-165,540,000	-447,948,000
Transfers in	515,000	'	'	'
Transfers out	'	-870,000	'	-619,000
Realized gains/ (losses)	1,386,000	18,842,000	9,508,000	38,765,000
Unrealized gains/ (losses)	1,649,000	-9,639,000	-139,000	6,006,000
Ending balance	168,626,000	212,881,000	168,626,000	212,881,000
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	10,846,000	254,000	6,643,000	5,218,000
Purchases	-8,439,000	-223,000	-16,751,000	-5,873,000
Sales	'	'	'	745,000
Transfers in	'	'	'	'
Transfers out	'	'	'	'
Realized gains/(losses)	8,439,000	223,000	16,751,000	5,115,000
Unrealized gains/ (losses)	-679,000	6,327,000	3,524,000	1,376,000
Ending balance	10,167,000	6,581,000	10,167,000	6,581,000
Financial instruments and other inventory positions sold, but not yet purchased | Derivative contracts	'	'	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	-8,439,000	-223,000	-16,751,000	-5,873,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	'	'	'	-745,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	10,846,000	254,000	6,643,000	5,218,000
Transfers in	'	'	'	'
Transfers out	'	'	'	'
Realized gains/(losses)	8,439,000	223,000	16,751,000	5,115,000
Unrealized gains/ (losses)	-679,000	6,327,000	3,524,000	1,376,000
Ending balance	10,167,000	6,581,000	10,167,000	6,581,000
Financial instruments and other inventory positions owned	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	131,791,000	172,772,000	122,679,000	119,083,000
Purchases	58,028,000	99,763,000	132,378,000	448,986,000
Sales	-93,801,000	-111,198,000	-163,172,000	-437,592,000
Transfers in	515,000	'	'	'
Transfers out	'	-251,000	'	'
Realized gains/ (losses)	1,377,000	12,900,000	7,140,000	32,819,000
Unrealized gains/ (losses)	718,000	-6,684,000	-397,000	4,006,000
Ending balance	98,628,000	167,302,000	98,628,000	167,302,000
Financial instruments and other inventory positions owned | Convertible securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	'	1,308,000	'	'
Purchases	'	0	'	'
Sales	'	-1,615,000	'	'
Transfers in	'	0	'	'
Transfers out	'	-251,000	'	'
Realized gains/ (losses)	'	839,000	'	'
Unrealized gains/ (losses)	'	-281,000	'	'
Ending balance	'	0	'	0
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	'	100,000	100,000	'
Purchases	'	0	0	100,000
Sales	'	0	-100,000	'
Transfers in	'	0	0	'
Transfers out	'	0	0	'
Realized gains/ (losses)	'	0	0	'
Unrealized gains/ (losses)	'	0	0	'
Ending balance	0	100,000	0	100,000
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	1,306,000	1,433,000	1,433,000	1,429,000
Purchases	'	'	'	1,000
Sales	'	'	'	'
Transfers in	'	'	'	'
Transfers out	'	'	'	'
Realized gains/ (losses)	'	'	'	-266,000
Unrealized gains/ (losses)	'	'	-127,000	269,000
Ending balance	1,306,000	1,433,000	1,306,000	1,433,000
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	732,000	656,000	656,000	656,000
Purchases	'	'	'	'
Sales	'	'	-25,000	'
Transfers in	'	'	'	'
Transfers out	'	'	'	'
Realized gains/ (losses)	'	'	6,000	'
Unrealized gains/ (losses)	-1,000	'	94,000	'
Ending balance	731,000	656,000	731,000	656,000
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	129,126,000	151,396,000	119,799,000	116,171,000
Purchases	58,028,000	99,763,000	129,764,000	448,175,000
Sales	-93,801,000	-97,246,000	-163,047,000	-424,274,000
Transfers in	515,000	'	'	'
Transfers out	'	'	'	'
Realized gains/ (losses)	1,377,000	-276,000	9,748,000	20,562,000
Unrealized gains/ (losses)	29,000	3,405,000	-990,000	-3,592,000
Ending balance	95,274,000	157,042,000	95,274,000	157,042,000
Financial instruments and other inventory positions owned | Derivative contracts	'	'	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	'	'	2,614,000	710,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	12,337,000	'	13,318,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	627,000	17,879,000	691,000	827,000
Transfers in	'	'	'	'
Transfers out	'	'	'	'
Realized gains/ (losses)	'	12,337,000	-2,614,000	12,523,000
Unrealized gains/ (losses)	690,000	-9,808,000	626,000	7,329,000
Ending balance	1,317,000	8,071,000	1,317,000	8,071,000
Investments [Member]	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Beginning balance	58,567,000	53,567,000	49,240,000	33,245,000
Purchases	10,500,000	'	20,500,000	15,363,000
Sales	-9,000	-10,356,000	-2,368,000	-10,356,000
Transfers in	'	'	'	'
Transfers out	'	-619,000	'	-619,000
Realized gains/ (losses)	9,000	5,942,000	2,368,000	5,946,000
Unrealized gains/ (losses)	931,000	-2,955,000	258,000	2,000,000
Ending balance	$69,998,000	$45,579,000	$69,998,000	$45,579,000

Variable_Interest_Entities_Add

Variable Interest Entities - Additional Information (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entities Disclosure [Abstract]	'	'
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	$700,000,000	$800,000,000
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	0	0
Variable interest entities, exposure to loss	$9,700,000	'

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, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Disclosure Amounts Receivable From Brokers Dealers And Clearing Organizations [Abstract]	'	'
Receivable arising from unsettled securities transactions	$156,686	$59,657
Deposits paid for securities borrowed	33,310	36,278
Receivable from clearing organizations	14,419	966
Deposits with clearing organizations	33,265	20,995
Securities failed to deliver	17,958	593
Other	35,552	8,624
Brokers, dealers and clearing organizations	$291,190	$127,113

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, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Disclosure Amounts Payable To Brokers Dealers And Clearing Organizations [Abstract]	'	'
Payable arising from unsettled securities transactions	$63,836	$5,643
Payable to clearing organizations	8,590	9,462
Securities failed to receive	7,101	744
Other	4,817	11,873
Brokers, dealers and clearing organizations	$84,344	$27,722

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, 2014
In Thousands, unless otherwise specified
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	$66,973
Fair Market Value	75,282
Maturity up to 30 days [Member] | Asset-backed securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	11,796
Fair Market Value	16,075
Maturity up to 30 days [Member] | Asset-backed securities | Minimum	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	1.75%
Maturity up to 30 days [Member] | Asset-backed securities | Maximum	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	1.84%
Maturity 30 to 90 Days [Member] | Asset-backed securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	4,665
Fair Market Value	6,218
Interest Rate	1.88%
On demand maturities [Member] | Fixed income securities	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	10,907
Fair Market Value	11,488
Interest Rate	0.55%
On demand maturities [Member] | US Government Corporations and Agencies Securities [Member]	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Repurchase Liabilities	39,605
Fair Market Value	$41,501
On demand maturities [Member] | US Government Corporations and Agencies Securities [Member] | Minimum	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	0.25%
On demand maturities [Member] | US Government Corporations and Agencies Securities [Member] | Maximum	'
Assets Sold under Agreements to Repurchase [Line Items]	'
Interest Rate	0.30%

Collateralized_Securities_Tran3

Collateralized Securities Transactions - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Assets Sold under Agreements to Repurchase [Line Items]	'	'	'
Other Comprehensive (Income) Loss, Net of Tax, Portion Attributable to Noncontrolling Interest	$0	$0	'
Reverse Repurchase, Offset Value	0	'	0
Securities purchased under agreements to resell, securities borrowed and margin agreements on terms that permit to repledge or resell the securities to others	300,500,000	'	212,400,000
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	292,700,000	'	194,900,000
Securities loaned	0	'	0
Financing activities [Member]	'	'	'
Assets Sold under Agreements to Repurchase [Line Items]	'	'	'
Prior Period Reclassification Adjustment	'	$36,900,000	'

Investments_Details

Investments (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments [Abstract]	'	'
Investments at fair value	$92,173	$69,930
Investments at cost	7,683	20,709
Investments accounted for under the equity method	25,311	21,404
Total investments	125,167	112,043
Less investments attributable to noncontrolling interests	-30,344	-21,137
Investments less portion attributable to noncontolling interest	$94,823	$90,906

Investments_Additional_Informa

Investments - Additional Information (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Investment [Line Items]	'	'
Investments	$125,167,000	$112,043,000
Estimated fair market value of investments carried at cost	13,000,000	'
Debt investment in private company [Member]	'	'
Investment [Line Items]	'	'
Valuation Allowances and Reserves, Balance	$0	'

Other_Assets_Details

Other Assets (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'	'
Net deferred income tax assets	$37,495	$36,252
Fee receivables	24,764	34,415
Accrued interest receivables	10,856	9,793
Forgivable loans, net	9,649	7,879
Prepaid expenses	3,697	5,237
Other	9,576	8,516
Total other assets	$96,037	$102,092

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

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Jul. 16, 2013

Sep. 30, 2014

Capital Markets

Capital Markets

Capital Markets

Capital Markets

Asset Mgmt [Member]

Asset Mgmt [Member]

Asset Mgmt [Member]

Asset Mgmt [Member]

Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.

Seattle-Northwest Securities Corporation and Edgeview Partners, L.P.

Capital Markets

Goodwill

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill beginning balance

'

'

$210,634

'

'

'

$13,790

'

'

'

$196,844

'

'

'

Goodwill acquired

'

'

'

'

'

'

0

'

'

'

'

'

-15,034

'

Impairment charge

'

'

'

'

'

'

0

'

'

'

'

'

'

'

Goodwill ending balance

211,878

'

211,878

'

15,034

'

15,034

'

196,844

'

196,844

'

15,034

'

Intangible assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangible assets beginning balance

'

'

39,930

'

'

'

5,316

'

'

'

34,614

'

'

'

Amortization of intangible assets

-2,318

-2,899

-6,954

-6,221

-743

-1,238

-2,229

-1,238

-1,575

-1,661

-4,725

-4,983

'

'

Intangible assets ending balance

32,976

'

32,976

'

3,087

'

3,087

'

29,889

'

29,889

'

'

'

Goodwill measurement period adjustment

'

'

$1,244

'

'

'

'

'

'

'

$0

'

'

$1,244

ShortTerm_Financing_Summary_of

Short-Term Financing - Summary of Short Term Financing and Weighted Average Interest Rate on Borrowings (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Short-term Debt [Line Items]	'	'
Oustanding Balance	$338,795,000	$514,711,000
Commercial paper (secured)	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	247,795,000	280,294,000
Weighted Average Interest Rate	1.51%	1.59%
Prime broker arrangement	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	0	234,417,000
Weighted Average Interest Rate	'	0.90%
Line of Credit [Member]	'	'
Short-term Debt [Line Items]	'	'
Oustanding Balance	$91,000,000	$0
Weighted Average Interest Rate	1.50%	'

ShortTerm_Financing_Additional

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

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Commercial paper (secured)

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]

program

Minimum

Maximum

CP Series A

CP Series II A

CP Series III A

Covenant Requirement

Committed Credit Facility [Member]

Uncommitted 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

'

'

'

'

'

'

'140 days

'200 days

'35 days

'

'

'

'

'

'

Net Capital

$163,200,000

'

'

'

'

'

'

'

'

$120,000,000

'

'

'

'

'

Debt term

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

Line of credity, maximum borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

250,000,000

185,000,000

'

Minimum net capital required

'

'

'

'

'

'

'

'

'

'

'

'

'

'

120,000,000

Short-term financing

$338,795,000

$514,711,000

$247,795,000

$280,294,000

'

'

'

'

'

'

$91,000,000

$0

$0

$91,000,000

'

Number of banks

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

Variable_Rate_Senior_Notes_Add

Variable Rate Senior Notes - Additional Information (Details) (USD $)	9 Months Ended				9 Months Ended		9 Months Ended
	Sep. 30, 2014	Nov. 30, 2012	Jun. 02, 2014	Nov. 30, 2012	Sep. 30, 2014	Nov. 30, 2012	Sep. 30, 2014	Sep. 30, 2014
		Senior Notes	Senior Notes	Senior Notes	Senior Notes	Senior Notes	Senior Notes	Senior Notes
		class	Class A Variable Rate Senior Notes Due May 2017 [Member]	Class A Variable Rate Senior Notes Due May 2017 [Member]	Class A Variable Rate Senior Notes Due May 2017 [Member]	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
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'
Face amount	'	$125,000,000	$50,000,000	$50,000,000	'	$75,000,000	'	'
Number of classes of notes	'	2	'	'	'	'	'	'
Basis spread on variable rate	'	'	'	'	3.00%	'	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

Contingencies_and_Commitments_1

Contingencies and Commitments - Aggregate Minimum Lease Commitments under Operating Leases (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Remainder of 2014	$2,651
2015	12,244
2016	11,901
2017	9,877
2018	9,563
Thereafter	35,441
Total	$81,677

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2012	Sep. 30, 2014	Sep. 30, 2013
Stockholders Equity Note [Line Items]	'	'	'	'
Repurchase of common stock, authorized amount	$100,000,000	$100,000,000	'	'
Shares of common stock purchased from restricted stock award related to recipients' employment tax obligations	'	'	251,004	'
Repurchase of common stock for employee tax withholding	'	'	10,563,000	'
Number of common stock issued for retirement plan obligations	'	'	103,598	96,049
Stock Issued During Period, Value, Treasury Stock Reissued	'	'	4,156,000	3,939,000
Reissuance of treasury shares as a result of employee vesting	'	'	635,347	770,189
Retirement Plan	'	'	'	'
Stockholders Equity Note [Line Items]	'	'	'	'
Stock Issued During Period, Value, Treasury Stock Reissued	'	'	$4,200,000	$3,900,000

Noncontrolling_Interests_Addit

Noncontrolling Interests - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	$140,715	$147,396
Municipal bond fund	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	110,400	126,300
Merchant banking fund	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	22,900	14,100
Other private equity investments	'	'
Noncontrolling Interest Note [Line Items]	'	'
Noncontrolling interests	$7,400	$7,000

Noncontrolling_Interest_Rollfo

Noncontrolling Interest - Rollforward (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Stockholders' Equity Attributable to Parent	'	'	$734,676	'
Noncontrolling interest, beginning balance	'	'	147,396	'
Beginning Balance	'	'	882,072	'
Net income/(loss) applicable to Piper Jaffray Companies	14,668	5,322	50,629	17,956
Net income	17,096	7,645	60,350	19,510
Amortization/issuance of restricted stock	'	'	22,114	'
Stock Issued During Period, Value, Stock Options Exercised	'	'	3,644	'
Repurchase of common stock for employee tax withholding	'	'	-10,563	'
Issuance of treasury shares for 401k match	'	'	4,156	3,939
Shares reserved to meet deferred compensation obligations	'	'	120	'
Other comprehensive income	-399	137	-143	16
Fund Capital Contributions	'	'	-16,402	'
Stockholders' Equity Attributable to Parent	804,633	'	804,633	'
Noncontrolling interest, ending balance	140,715	'	140,715	'
Ending Balance	945,348	'	945,348	'
Parent	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Amortization/issuance of restricted stock	'	'	22,114	'
Stock Issued During Period, Value, Stock Options Exercised	'	'	3,644	'
Repurchase of common stock for employee tax withholding	'	'	-10,563	'
Issuance of treasury shares for 401k match	'	'	4,156	'
Shares reserved to meet deferred compensation obligations	'	'	120	'
Other comprehensive income	'	'	-143	'
Fund Capital Contributions	'	'	0	'
Noncontrolling Interests	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Amortization/issuance of restricted stock	'	'	0	'
Stock Issued During Period, Value, Stock Options Exercised	'	'	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	'	'	($16,402)	'

Compensation_Plans_Additional_

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

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

15-May-12

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2010

Sep. 30, 2014

plan

plan

Minimum

Maximum [Member]

Maximum [Member]

Annual Grant [Member]

Sign On Grant [Member]

Sign On 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

Deferred Compensation Plans [Member]

New Employees [Member]

New Employees [Member]

Minimum

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

Award vesting period in years

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'5 years

'

Annual grant expense period

'

'

'

'

'

'

'

'1 year

'2 years

'5 years

'

'

'

'

'

'

'

'

'

'

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

$500,000

$100,000

$600,000

$800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted stock units, performance period

'

'

'

'

'

'

'

'

'

'

'36 months

'

'

'

'

'

'

'

'

'

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

'

'

'2 years 6 months

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

115,290

'

'

415,413

'

'

'

158,801

'

Compensation expense related to employee restricted stock awards

7,200,000

6,000,000

20,500,000

10,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

2,800,000

2,300,000

8,000,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized compensation cost related to restricted stock

11,500,000

'

11,500,000

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

Mutual funds

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,500,000

Deferred liabilities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$6,500,000

Acquisition related compensation awards vesting period

'

'

'3 years

'

'2 years

'

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Compensation_Plans_Summary_of_

Compensation Plans - Summary of Outstanding Equity Awards (Details)	Sep. 30, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	1,212,819	'
Stock options outstanding	261,259	469,289
Restricted stock related to compensation [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	1,108,323	'
Restricted Stock related to deal consideration [Member] | ARI [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	104,496	'
Restricted Stock Units	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	405,826	290,536
Amended And Restated 2003 Annual And Long -Term Incentive Plan	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock options outstanding	261,259	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Restricted stock related to compensation [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	1,079,164	'
Amended And Restated 2003 Annual And Long -Term Incentive Plan | Restricted Stock Units	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	405,826	'
2010 Employment Inducement Award Plan | Restricted stock related to compensation [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	29,159	'
Annual Grant [Member] | Amended And Restated 2003 Annual And Long -Term Incentive Plan | Restricted stock related to compensation [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	811,513	'
Sign On Grant [Member] | Amended And Restated 2003 Annual And Long -Term Incentive Plan | Restricted stock related to compensation [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Restricted stock outstanding	267,651	'

Compensation_Plans_RSU_Valuati

Compensation Plans - RSU Valuation Assumptions (Details) (Restricted Stock Units)	9 Months Ended
	Sep. 30, 2014
Grant Year 2014 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk-free Interest Rate	0.82%
Expected Stock Price Volatility	41.30%
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) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'	'	'2 years 6 months	'
Allocated Share-based Compensation Expense	$7.20	$6	$20.50	$10.40
Unvested Restricted Stock or Stock Units	'	'	'	'
Ending Balance	1,212,819	'	1,212,819	'
Weighted Average Grant Date Fair Value (in dollars per share)	'	'	'	'
Restricted Stock Award, Forfeitures	0.5	0.1	0.6	0.8
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$2.80	$2.30	$8	$4
Restricted Stock	'	'	'	'
Unvested Restricted Stock or Stock Units	'	'	'	'
Beginning Balance	'	'	1,582,062	'
Granted	'	'	415,413	'
Vested	'	'	-765,283	'
Cancelled	'	'	-19,373	'
Ending Balance	1,212,819	'	1,212,819	'
Weighted Average Grant Date Fair Value (in dollars per share)	'	'	'	'
Beginning Balance	'	'	$35.25	'
Granted	'	'	$40.34	'
Vested	'	'	$35.17	'
Cancelled	'	'	$36.19	'
Ending Balance	$37.03	'	$37.03	'

Compensation_Plans_Unvested_Re1

Compensation Plans - Unvested Restricted Stock Units (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
Unvested Restricted Stock or Stock Units	'
Ending Balance	1,212,819
Restricted Stock Units	'
Unvested Restricted Stock or Stock Units	'
Beginning Balance	290,536
Granted	115,290
Vested	0
Cancelled	0
Ending Balance	405,826
Weighted Average Grant Date Fair Value (in dollars per share)	'
Beginning Balance	$15.83
Granted	$23.42
Vested	$0
Cancelled	$0
Ending Balance	$17.99

Compensation_Plans_Stock_Optio

Compensation Plans - Stock Options (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Restricted Stock Award, Forfeitures	$500,000	$100,000	$600,000	$800,000	'
Options exercisable at period end	$45.83	'	$45.83	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	'	'	1,100,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	94,478	0	'
Options Outstanding	'	'	'	'	'
Beginning Balance	'	'	469,289	'	'
Granted	'	'	0	'	'
Exercised	'	'	-94,478	0	'
Cancelled	'	'	-55	'	'
Expired	'	'	-113,497	'	'
Ending Balance	261,259	'	261,259	'	469,289
Options exercisable at period end	261,259	'	261,259	'	'
Weighted Average Exercise Price (in dollars per share)	'	'	'	'	'
Beginning Balance	'	'	$44.83	'	'
Granted	'	'	$0	'	'
Exercised	'	'	$38.57	'	'
Cancelled	'	'	$39.62	'	'
Expired	'	'	$47.72	'	'
Ending Balance	$45.83	'	$45.83	'	$44.83
Weighted Average Remaining Contractual Term (in Years)	'	'	'	'	'
Weighted Average Remaining Contractual Term (in Years)	'	'	'2 years	'	'2 years
Options exercisable at period end	'	'	'2 years	'	'
Aggregate Intrinsic Value	'	'	'	'	'
Aggregate Intrinsic Value of Stock Options	2,527,750	'	2,527,750	'	288,318
Options exercisable at end of period	2,527,750	'	2,527,750	'	'
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	'	'	$400,000	'	'

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income/(loss) from continuing operations	$14,668	$6,851	$50,629	$21,877
Net loss from discontinued operations	0	-1,529	0	-3,921
Net income applicable to Piper Jaffray Companies	14,668	5,322	50,629	17,956
Earnings allocated to participating securities	-1,116	-496	-4,243	-1,793
Net income applicable to Piper Jaffray Companies' common shareholders	$13,552	$4,826	$46,386	$16,163
Shares for basic and diluted calculations:	'	'	'	'
Average shares used in basic computation	15,066,000	14,621,000	14,880,000	15,271,000
Incremental common share attributable to share-based payment arrangements	63,000	5,000	54,000	13,000
Average shares used in diluted computation	15,129,000	14,626,000	14,934,000	15,284,000
Earnings/(loss) per basic common share	'	'	'	'
Income from continuing operations	$0.90	$0.42	$3.12	$1.29
Loss from discontinued operations	$0	($0.09)	$0	($0.23)
Earnings per basic common share	$0.90	$0.33	$3.12	$1.06
Earnings/(loss) per diluted common share	'	'	'	'
Income from continuing operations	$0.90	$0.42	$3.11	$1.29
Loss from discontinued operations	$0	($0.09)	$0	($0.23)
Earnings per diluted common share	$0.90	$0.33	$3.11	$1.06
Weighted average participating shares outstanding	1,245,665	1,504,665	1,366,489	1,695,130

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Investment banking	$94,911	$62,848	$287,198	$156,924
Institutional sales and trading	35,923	35,318	114,485	100,076
Asset management	21,595	18,701	64,820	55,584
Investment income	2,690	5,279	12,379	8,285
Net revenues	159,426	128,314	497,590	337,619
Operating expenses	133,734	116,254	408,768	304,058
Segment pre-tax operating income/(loss)	25,692	12,060	88,822	33,561
Pre-tax operating margin	16.10%	9.40%	17.90%	9.90%
Intangible asset amortization expense	2,318	2,899	6,954	6,221
Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Investment banking	95,024	63,033	287,519	157,221
Institutional sales and trading	39,448	40,041	128,397	114,809
Asset management	1,387	1,094	4,512	2,677
Investment income	5,224	7,892	20,600	14,213
Interest Expense, Long-term Debt	-1,613	-1,797	-5,058	-5,618
Net revenues	139,470	110,263	435,970	283,302
Operating expenses	119,001	103,906	364,622	266,301
Segment pre-tax operating income/(loss)	20,469	6,357	71,348	17,001
Pre-tax operating margin	14.70%	5.80%	16.40%	6.00%
Intangible asset amortization expense	743	1,238	2,229	1,238
Asset Mgmt [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Management fees	19,738	17,547	59,474	52,191
Performance fees	470	60	834	716
Asset management	20,208	17,607	60,308	52,907
Investment income	-252	444	1,312	1,410
Net revenues	19,956	18,051	61,620	54,317
Operating expenses	14,733	12,348	44,146	37,757
Segment pre-tax operating income/(loss)	5,223	5,703	17,474	16,560
Pre-tax operating margin	26.20%	31.60%	28.40%	30.50%
Intangible asset amortization expense	1,575	1,661	4,725	4,983
Equities Financing [Member] | Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Investment banking	14,269	30,010	93,628	66,085
Debt Financing [Member] | Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Investment banking	14,435	12,808	48,148	51,971
Advisory Services [Member] | Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Investment banking	66,320	20,215	145,743	39,165
Equity securities | Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Institutional sales and trading	16,711	22,958	59,337	65,077
Debt securities | Capital Markets	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Institutional sales and trading	$22,737	$17,083	$69,060	$49,732

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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	$159,426	$128,314	$497,590	$337,619
United States	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	153,375	126,458	486,251	329,379
Europe	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Net revenues	$6,051	$1,856	$11,339	$8,240

Segment_Reporting_LongLived_As

Segment Reporting - Long-Lived Assets By Geographic Region (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	$299,722	$302,930
United States	'	'
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	293,823	296,516
Europe	'	'
Long-Lived Assets by Geographical Areas [Line Items]	'	'
Long Lived Assets	$5,899	$6,414

Net_Capital_Requirements_and_O1

Net Capital Requirements and Other Regulatory Matters - Additional Information (Detail) (USD $)	Sep. 30, 2014
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%
Amount of capital that exceeds the minimum net capital required	163,200,000
Minimum net capital required	164,200,000
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
Commercial Paper [Member] | Covenant Requirement	'
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]	'
Amount of capital that exceeds the minimum net capital required	$120,000,000

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Income Taxes at Statutory Rates to Effective Tax Rates (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Effective Income Tax Rate Reconciliation, Percent	36.90%	29.60%	36.00%	31.60%

Restructuring_Details

Restructuring (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Restructuring Cost and Reserve [Line Items]	'
Restructuring Charges	$2.90
Severance Costs	2.1
Leased Office Space [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Other Restructuring Costs	0.5
Contract Termination [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Other Restructuring Costs	$0.30