Piper Sandler Companies (PIPR) 10-Q 1 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 23, 2015
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	PJC
Entity Registrant Name	Piper Jaffray Companies
Entity Central Index Key	1230245
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		15,975,385

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Condition (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Cash and cash equivalents	$9,382	$15,867
Cash and cash equivalents segregated for regulatory purposes	27,019	25,011
Receivables:
Customers	26,500	9,658
Brokers, dealers and clearing organizations	202,212	161,009
Securities purchased under agreements to resell	385,707	308,165
Financial instruments and other inventory positions owned	535,461	507,794
Financial instruments and other inventory positions owned and pledged as collateral	1,211,706	1,108,567
Total financial instruments and other inventory positions owned	1,747,167	1,616,361
Fixed assets (net of accumulated depreciation and amortization of $48,223 and $47,327, respectively)	18,805	18,171
Goodwill	211,878	211,878
Intangible assets (net of accumulated amortization of $42,914 and $41,141, respectively)	28,885	30,658
Investments	144,910	126,840
Other assets	114,564	100,299
Total assets	2,917,029	2,623,917
Liabilities and Shareholders’ Equity
Short-term financing	517,522	377,767
Variable rate senior notes	125,000	125,000
Payables:
Customers	34,922	13,328
Brokers, dealers and clearing organizations	176,454	25,564
Securities sold under agreements to repurchase	169,227	102,646
Financial instruments and other inventory positions sold, but not yet purchased	778,268	738,124
Accrued compensation	81,740	228,877
Other liabilities and accrued expenses	46,762	43,151
Total liabilities	1,929,895	1,654,457
Shareholders’ equity:
Common stock, $0.01 par value: Shares authorized: 100,000,000 at March 31, 2015 and December 31, 2014; Shares issued: 19,509,433 at March 31, 2015 and 19,523,371 at December 31, 2014; Shares outstanding: 14,999,604 at March 31, 2015 and 15,265,420 at December 31, 2014	195	195
Additional paid-in capital	754,481	735,415
Retained earnings	244,037	227,065
Less common stock held in treasury, at cost: 4,509,829 shares at March 31, 2015 and 4,257,951 shares at December 31, 2014	-167,664	-143,140
Accumulated other comprehensive income/(loss)	-98	377
Total common shareholders’ equity	830,951	819,912
Noncontrolling interests	156,183	149,548
Total shareholders’ equity	987,134	969,460
Total liabilities and shareholders’ equity	$2,917,029	$2,623,917

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Accumulated depreciation and amortization on fixed assets	$48,223	$47,327
Accumulated amortization on intangible assets	$42,914	$41,141
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	19,509,433	19,523,371
Common stock, shares outstanding	14,999,604	15,265,420
Common stock held in treasury, shares	4,509,829	4,257,951

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Investment banking	$87,077	$88,474
Institutional brokerage	36,036	44,034
Asset management	20,522	20,959
Interest	12,205	13,659
Investment income	12,591	6,768
Total revenues	168,431	173,894
Interest expense	6,560	5,761
Net revenues	161,871	168,133
Non-interest expenses:
Compensation and benefits	95,857	100,489
Occupancy and equipment	6,783	6,778
Communications	6,328	5,955
Trade execution and clearance	1,997	1,834
Marketing and business development	6,982	6,251
Outside services	8,184	8,768
Intangible asset amortization expense	1,773	2,318
Other operating expenses	2,675	3,027
Total non-interest expenses	130,579	135,420
Income from before income tax expense	31,292	32,713
Income tax expense	9,490	9,827
Net income	21,802	22,886
Net income applicable to noncontrolling interests	4,830	5,138
Net income applicable to Piper Jaffray Companies	16,972	17,748
Net income applicable to Piper Jaffray Companies’ common shareholders	$15,810	$16,089
Earnings per common share
Basic	$1.03	$1.10
Diluted	$1.03	$1.10
Weighted average number of common shares outstanding
Basic	15,294	14,612
Diluted	15,332	14,657

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$21,802	$22,886
Other comprehensive income/(loss), net of tax:
Foreign currency translation adjustment	-475	51
Comprehensive income	21,327	22,937
Comprehensive income applicable to noncontrolling interests	4,830	5,138
Comprehensive income applicable to Piper Jaffray Companies	$16,497	$17,799

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Activities:
Net income	$21,802	$22,886
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization of fixed assets	1,215	1,418
Deferred income taxes	-10,162	-8,142
Stock-based and deferred compensation	13,756	5,375
Amortization of intangible assets	1,773	2,318
Amortization of forgivable loans	1,280	1,327
Decrease/(increase) in operating assets:
Cash and cash equivalents segregated for regulatory purposes	-2,008	-1,129
Receivables:
Customers	-16,842	-8,152
Brokers, dealers and clearing organizations	-41,203	-103,450
Securities purchased under agreements to resell	-77,542	-8,990
Net financial instruments and other inventory positions owned	-90,662	38,500
Investments	-18,070	-18,212
Other assets	-25,932	792
Payables:
Customers	21,594	7,109
Brokers, dealers and clearing organizations	150,890	83,258
Accrued compensation	-128,977	-64,516
Other liabilities and accrued expenses	3,633	-13,646
Net cash used in operating activities	-175,131	-46,970
Investing Activities:
Purchases of fixed assets, net	-1,896	-607
Net cash used in investing activities	-1,896	-607
Financing Activities:
Increase/(decrease) in short-term financing	139,755	-78,902
Increase in securities sold under agreements to repurchase	66,581	47,649
Increase/(decrease) in noncontrolling interests	1,805	-2,909
Repurchase of common stock	-42,566	-7,346
Excess/(reduced) tax benefit from stock-based compensation	3,662	-47
Proceeds from stock option exercises	1,562	273
Net cash provided by/(used in) financing activities	170,799	-41,282
Currency adjustment:
Effect of exchange rate changes on cash	-257	11
Net decrease in cash and cash equivalents	-6,485	-88,848
Cash and cash equivalents at beginning of year	15,867	123,683
Cash and cash equivalents at end of year	9,382	34,835
Supplemental disclosure of cash flow information –
Interest	6,427	6,019
Income taxes	15,871	19,972
Non-cash financing activities –
103,598 shares for the three months ended March 31, 2014	0	4,156
550,650 shares and 402,074 shares for the three months ended March 31, 2015 and 2014, respectively	$30,429	$16,131

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Statement of Cash Flows [Abstract]
Number of common stock issued for retirement plan obligations	0	103,598
Number of restricted common stock issued for annual equity award	550,650	402,074

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
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.
	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.
	Basis of Presentation
	The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and the rules and regulations of the Securities and Exchange Commission ("SEC"). Pursuant to this guidance, certain information and disclosures have been omitted that are included within complete annual financial statements. Except as disclosed herein, there have been no material changes in the information reported in the financial statements and related disclosures in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.
	The consolidated financial statements 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.
	Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates and assumptions are based on the best information available, actual results could differ from those estimates.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
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, 2014 for a full description of the Company's significant accounting policies.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	Future Adoption of New Applicable Accounting Standards
	Revenue Recognition
	In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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.
	Consolidation
	In February 2015, the FASB issued ASU No. 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis" ("ASU 2015-02"). ASU 2015-02 makes several modifications to the consolidation guidance for variable interest entities ("VIEs") and general partners' investments in limited partnerships, as well as modifications to the evaluation of whether limited partnerships are VIEs or voting interest entities. It is effective for annual and interim periods beginning after December 15, 2015. Early adoption is permitted. The Company is evaluating the impact of the amended guidance on its consolidated financial statements.

Financial_Instruments_and_Othe

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased	3 Months Ended
	Mar. 31, 2015
Securities Owned and Sold, Not yet Purchased [Abstract]
Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, 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:
		March 31,				December 31,
	(Dollars in thousands)	2015				2014
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	60,806			$	50,365
	Convertible securities	167,169				156,685
	Fixed income securities	30,702				48,651
	Municipal securities:
	Taxable securities	271,821				312,753
	Tax-exempt securities	597,299				559,704
	Short-term securities	87,581				68,717
	Asset-backed securities	148,957				125,065
	U.S. government agency securities	333,053				244,046
	U.S. government securities	826				2,549
	Derivative contracts	48,953				47,826
	Total financial instruments and other inventory positions owned	1,747,167				1,616,361
	Less noncontrolling interests (1)	(305,932		)		(267,742		)
		$	1,441,235			$	1,348,619
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	158,297			$	154,589
	Convertible securities	269				—
	Fixed income securities	30,293				21,460
	U.S. government agency securities	20,225				27,735
	U.S. government securities	558,477				523,527
	Derivative contracts	10,707				10,813
	Total financial instruments and other inventory positions sold, but not yet purchased	778,268				738,124
	Less noncontrolling interests (2)	(94,831		)		(98,669		)
		$	683,437			$	639,455
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $111.6 million and $123.3 million of taxable municipal securities, $188.9 million and $139.5 million of tax-exempt municipal securities, and $5.4 million and $4.9 million of derivative contracts as of March 31, 2015 and December 31, 2014, respectively.
	-2	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $93.7 million and $97.6 million of U.S. government securities, and $1.1 million of derivative contracts as of March 31, 2015 and December 31, 2014, respectively.
	At March 31, 2015 and December 31, 2014, financial instruments and other inventory positions owned in the amount of $1.2 billion and $1.1 billion, 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.
	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. The total absolute notional contract amount, representing the absolute value of the sum of gross long and short derivative contracts, provides an indication of the volume of the Company's derivative activity and does not represent gains and losses. The following table presents the gross fair market value and the total absolute notional contract amount of the Company's outstanding derivative instruments, prior to counterparty netting, by asset or liability position:
			March 31, 2015										December 31, 2014
	(Dollars in thousands)		Derivative				Derivative				Notional		Derivative		Derivative		Notional
	Derivative Category		Assets (1)				Liabilities (2)				Amount		Assets (1)		Liabilities (2)		Amount
	Interest rate
	Customer matched-book		$	486,922			$	464,143			$	4,838,143	$	447,987	$	425,227	$	4,860,302
	Trading securities		1,222				9,184				411,750		140		8,242		297,250
	Credit default swap index
	Trading securities		5,769				6,358				247,721		5,808		5,188		267,796
	Equity option
	Trading securities		156				147				49,585		76		189		19,380
			$	494,069			$	479,832			$	5,547,199	$	454,011	$	438,846	$	5,444,728
	-1	The gross fair market value of derivative assets are included within financial instruments and other inventory positions owned on the consolidated statements of financial condition.
	-2	The gross fair market value of derivative liabilities are included within financial instruments and other inventory positions sold, but not yet purchased on the consolidated statements of financial condition.
	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
	(Dollars in thousands)				March 31,
	Derivative Category		Operations Category		2015				2014
	Interest rate derivative contract		Investment banking		$	(520	)		$	(524	)
	Interest rate derivative contract		Institutional brokerage		679				532
	Credit default swap index contract		Institutional brokerage		4,607				(1,254		)
	Equity option derivative contract		Institutional brokerage		35				948
					$	4,801			$	(298	)
	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 March 31, 2015, the Company had $27.6 million of uncollateralized credit exposure with these counterparties (notional contract amount of $189.0 million), including $18.4 million of uncollateralized credit exposure with one counterparty.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2015
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.
	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.
	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 50-1,068 basis points (“bps”) on spreads over U.S. treasury securities, or models based upon prepayment expectations ranging from 50-490 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, 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 and partnerships, investments in public companies, investments in registered mutual funds, warrants of public and private companies and private company debt. 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. Investments 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 $19.3 million and $18.4 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 March 31, 2015 and December 31, 2014, 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 $0.8 million and $0.3 million for the three months ended March 31, 2015 and 2014, 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 March 31, 2015:
		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 - 60%		19.40%
	Short-term securities	Discounted cash flow		Expected recovery rate (% of par) (2)	66 - 94%		91.00%
	Asset-backed securities:
	Collateralized by residential mortgages	Discounted cash flow		Credit default rates (3)	1 - 5%		3.20%
				Prepayment rates (4)	0 - 26%		5.50%
				Loss severity (3)	32 - 90%		58.20%
				Valuation yields (3)	2 - 8%		4.80%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	4 - 23 bps		8.6 bps
	Investments at fair value:
	Warrants in public and private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 40%		39.30%
	Warrants in private companies	Black-Scholes option pricing model		Stock volatility factors of comparable companies (2)	29 - 57%		42.00%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 6 times		4.6 times
				EBITDA multiple (2)	9 - 12 times		9.7 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)	0 - 26 bps		6.0 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 March 31, 2015:
											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	$	48,372		$	12,434		$	—		$	—		$	60,806
	Convertible securities	—			167,169			—			—			167,169
	Fixed income securities	—			30,702			—			—			30,702
	Municipal securities:
	Taxable securities	—			271,821			—			—			271,821
	Tax-exempt securities	—			596,123			1,176			—			597,299
Short-term securities	—			86,861			720			—			87,581
Asset-backed securities	—			1,080			147,877			—			148,957
U.S. government agency securities	—			333,053			—			—			333,053
U.S. government securities	826			—			—			—			826
Derivative contracts	156			492,691			1,222			(445,116		)	48,953
Total financial instruments and other inventory positions owned:	49,354			1,991,934			150,995			(445,116		)	1,747,167
Cash equivalents	865			—			—			—			865
Investments at fair value	29,613			—			87,468			—			117,081
Total assets	$	79,832		$	1,991,934		$	238,463		$	(445,116	)	$	1,865,113
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	155,331		$	2,966		$	—		$	—		$	158,297
Convertible securities	—			269			—			—			269
Fixed income securities	—			30,293			—			—			30,293
U.S. government agency securities	—			20,225			—			—			20,225
U.S. government securities	558,477			—			—			—			558,477
Derivative contracts	147			471,459			8,226			(469,125		)	10,707
Total financial instruments and other inventory positions sold, but not yet purchased:	$	713,955		$	525,212		$	8,226		$	(469,125	)	$	778,268
-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, 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	$	39,191		$	11,174		$	—		$	—		$	50,365
Convertible securities	—			156,685			—			—			156,685
Fixed income securities	—			48,651			—			—			48,651
Municipal securities:
Taxable securities	—			312,753			—			—			312,753
Tax-exempt securities	—			558,518			1,186			—			559,704
Short-term securities	—			67,997			720			—			68,717
Asset-backed securities	—			316			124,749			—			125,065
U.S. government agency securities	—			244,046			—			—			244,046
U.S. government securities	2,549			—			—			—			2,549
Derivative contracts	76			453,795			140			(406,185		)	47,826
Total financial instruments and other inventory positions owned:	41,816			1,853,935			126,795			(406,185		)	1,616,361
Cash equivalents	1,562			—			—			—			1,562
Investments at fair value	20,704			—			74,165			—			94,869
Total assets	$	64,082		$	1,853,935		$	200,960		$	(406,185	)	$	1,712,792
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Corporate securities:
Equity securities	$	153,254		$	1,335		$	—		$	—		$	154,589
Fixed income securities	—			21,460			—			—			21,460
U.S. government agency securities	—			27,735			—			—			27,735
U.S. government securities	523,527			—			—			—			523,527
Derivative contracts	189			430,835			7,822			(428,033		)	10,813
Total financial instruments and other inventory positions sold, but not yet purchased:	$	676,970		$	481,365		$	7,822		$	(428,033	)	$	738,124
-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 $238.5 million and $201.0 million, or 12.8 percent and 11.7 percent of financial instruments measured at fair value at March 31, 2015 and December 31, 2014, 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 three months ended March 31, 2015.
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:
																							Unrealized gains/
																							(losses) for assets/
	Balance at														Realized			Unrealized			Balance at		liabilities held at
	December 31,									Transfers			Transfers		gains/			gains/			March 31,		March 31,
(Dollars in thousands)	2014			Purchases			Sales			in			out		(losses) (1)			(losses) (1)			2015		2015 (1)
Assets:
Financial instruments and other inventory positions owned:
Municipal securities:
Tax-exempt securities	$	1,186		$	—		$	—		$	—		$	—	$	—		$	(10	)	$	1,176	$	(10	)
Short-term securities	720			—			—			—			—		—			—			720		—
Asset-backed securities	124,749			119,826			(98,947		)	—			—		2,490			(241		)	147,877		517
Derivative contracts	140			520			—			—			—		(520		)	1,082			1,222		1,222
Total financial instruments and other inventory positions owned:	126,795			120,346			(98,947		)	—			—		1,970			831			150,995		1,729
Investments at fair value	74,165			—			(182		)	—			—		182			13,303			87,468		13,303
Total assets	$	200,960		$	120,346		$	(99,129	)	$	—		$	—	$	2,152		$	14,134		$	238,463	$	15,032
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	7,822		$	(5,814	)	$	—		$	—		$	—	$	5,814		$	404		$	8,226	$	4,318
Total financial instruments and other inventory positions sold, but not yet purchased:	$	7,822		$	(5,814	)	$	—		$	—		$	—	$	5,814		$	404		$	8,226	$	4,318
-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 on the consolidated statements of operations.
																							Unrealized gains/
																							(losses) for assets/
	Balance at														Realized			Unrealized			Balance at		liabilities held at
	December 31,									Transfers			Transfers		gains/			gains/			March 31,		March 31,
(Dollars in thousands)	2013			Purchases			Sales			in			out		(losses) (1)			(losses) (1)			2014		2014 (1)
Assets:
Financial instruments and other inventory positions owned:
Corporate securities:
Fixed income securities	$	100		$	—		$	—		$	—		$	—	$	—		$	—		$	100	$	—
Municipal securities:
Tax-exempt securities	1,433			—			—			—			—		—			—			1,433		—
Short-term securities	656			—			—			—			—		—			—			656		—
Asset-backed securities	119,799			96,725			(114,506		)	—			—		6,270			(889		)	107,399		958
Derivative contracts	691			2,614			—			—			—		(2,614		)	(627		)	64		64
Total financial instruments and other inventory positions owned:	122,679			99,339			(114,506		)	—			—		3,656			(1,516		)	109,652		1,022
Investments at fair value	49,240			10,000			—			—			—		—			1,714			60,954		1,714
Total assets	$	171,919		$	109,339		$	(114,506	)	$	—		$	—	$	3,656		$	198		$	170,606	$	2,736
Liabilities:
Financial instruments and other inventory positions sold, but not yet purchased:
Derivative contracts	$	6,643		$	(16,751	)	$	—		$	—		$	—	$	16,751		$	(1,164	)	$	5,479	$	5,479
Total financial instruments and other inventory positions sold, but not yet purchased:	$	6,643		$	(16,751	)	$	—		$	—		$	—	$	16,751		$	(1,164	)	$	5,479	$	5,479
-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 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.

Receivables_from_and_Payables_

Receivables from and Payables to Brokers, Dealers and Clearing Organizations	3 Months Ended
	Mar. 31, 2015
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:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Receivable arising from unsettled securities transactions	$	49,725	$	52,571
	Deposits paid for securities borrowed	49,317		57,572
	Receivable from clearing organizations	11,203		4,933
	Deposits with clearing organizations	64,918		33,799
	Securities failed to deliver	7,254		1,753
	Other	19,795		10,381
		$	202,212	$	161,009
	Amounts payable to brokers, dealers and clearing organizations included:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Payable arising from unsettled securities transactions	$	148,353	$	11,048
	Payable to clearing organizations	9,204		5,185
	Securities failed to receive	7,394		2,430
	Other	11,503		6,901
		$	176,454	$	25,564
	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	3 Months Ended
	Mar. 31, 2015
Disclosure of Repurchase Agreements [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 the majority of its 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 $440.0 million and $369.7 million at March 31, 2015 and December 31, 2014, respectively, of which $428.2 million and $338.8 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 March 31, 2015:
		Repurchase		Fair Market
	(Dollars in thousands)	Liabilities		Value		Interest Rate
	Term up to 30 day maturities:
	Asset-backed securities	$	19,860	$	31,042	1.67 - 1.93%
	Term of 30 to 90 day maturities:
	Asset-backed securities	4,637		6,624		2.02%
	On demand maturities:
	Corporate securities:
	Fixed income securities	8,671		8,971		0.80%
	U.S. government agency securities	126,104		143,976		0.55 - 0.85%
	U.S. government securities	9,955		9,979		0.40%
		$	169,227	$	200,592
	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 March 31, 2015 and December 31, 2014, respectively, as a legal right of offset did not exist. The Company had no outstanding securities lending arrangements as of March 31, 2015 or December 31, 2014. See Note 4 for information related to the Company's offsetting of derivative contracts.

Investments

Investments	3 Months Ended
	Mar. 31, 2015
Investments, All Other 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:
		March 31,			December 31,
	(Dollars in thousands)	2015			2014
	Investments at fair value	$	117,081		$	94,869
	Investments at cost	3,805			8,214
	Investments accounted for under the equity method	24,024			23,757
	Total investments	144,910			126,840
	Less investments attributable to noncontrolling interests (1)	(32,710		)	(32,563		)
		$	112,200		$	94,277
	-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 March 31, 2015, investments carried on a cost basis had an estimated fair market value of $9.4 million. 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	3 Months Ended
	Mar. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets
	Other assets included:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Net deferred income tax assets	$	35,689	$	45,851
	Fee receivables	26,211		23,959
	Accrued interest receivables	10,560		10,061
	Forgivable loans, net	9,685		8,366
	Income tax receivables	17,792		—
	Prepaid expenses	5,215		6,067
	Other	9,412		5,995
	Total other assets	$	114,564	$	100,299

ShortTerm_Financing

Short-Term Financing	3 Months Ended
	Mar. 31, 2015
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
		March 31,		December 31,		March 31,	December 31,
	(Dollars in thousands)	2015		2014		2015	2014
	Commercial paper (secured)	$	245,994	$	238,013	1.52%	1.48%
	Prime broker arrangement	220,528		127,754		0.93%	0.91%
	Bank lines (secured)	51,000		12,000		1.11%	1.50%
	Total short-term financing	$	517,522	$	377,767
	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 March 31, 2015, the weighted average maturity of CP Series A and CP Series III A was 85 days and 12 days, respectively. As of March 31, 2015, the Company had no outstanding issuances under CP Series II A. 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 March 31, 2015 consisted of a one-year $250 million committed revolving credit facility with U.S. Bank, N.A., which was renewed in December 2014. 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 18, 2015. The Company pays a nonrefundable commitment fee on the unused portion of the facility on a quarterly basis. At March 31, 2015, the Company had $21.0 million in advances against this line of credit.
	The Company’s uncommitted secured lines at March 31, 2015 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 March 31, 2015, the Company had $30.0 million in advances against these lines of credit.

Variable_Rate_Senior_Notes

Variable Rate Senior Notes (Senior Notes)	3 Months Ended
	Mar. 31, 2015
Senior Notes
Debt Instrument [Line Items]
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 Pacific Investment Management Company LLC ("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 March 31, 2015, the Company was in compliance with all covenants.
	The Notes are recorded at amortized cost. As of March 31, 2015, the carrying value of the Notes approximated fair value.

Legal_Contingencies

Legal Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Legal Contingencies	Legal Contingencies
	The Company has been named as a defendant in various legal actions, including complaints and litigation and arbitration claims, arising from its business activities. Such actions include claims related to securities brokerage and investment banking activities, and certain class actions that primarily allege violations of securities laws and seek unspecified damages, which could be substantial. Also, the Company is involved from time to time in investigations and proceedings by governmental agencies and self-regulatory organizations (“SROs”) which could result in adverse judgments, settlement, penalties, fines or other relief.
	The Company has established reserves for potential losses that are probable and reasonably estimable that may result from pending and potential legal actions, investigations and regulatory proceedings. In many cases, however, it is inherently difficult to determine whether any loss is probable or even possible or to estimate the amount or range of any potential loss, particularly where proceedings may be in relatively early stages or where plaintiffs are seeking substantial or indeterminate damages. Matters frequently need to be more developed before a loss or range of loss can reasonably be estimated.
	Given uncertainties regarding the timing, scope, volume and outcome of pending and potential legal actions, investigations and regulatory proceedings and other factors, the amounts of reserves and ranges of reasonably possible losses are difficult to determine and of necessity subject to future revision. Subject to the foregoing, 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.

Shareholders_Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity
	Share Repurchases
	Effective October 1, 2014, the Company’s board of directors authorized the repurchase of up to $100.0 million in common shares through September 30, 2016. During the three months ended March 31, 2015, the Company repurchased 604,994 shares of the Company's common stock at an average price of $54.08 per share for an aggregate purchase price of $32.7 million related to this authorization. The Company has $67.3 million remaining under this authorization. The Company also purchases shares of common stock from restricted stock award recipients upon the award vesting as recipients sell shares to meet their employment tax obligations. The Company purchased 178,928 shares or $9.9 million of the Company’s common stock for this purpose during the three months ended March 31, 2015.
	Issuance of Shares
	The Company issues common shares out of treasury stock as a result of employee restricted share vesting and exercise transactions as discussed in Note 14. During the three months ended March 31, 2015 and 2014, the Company issued 518,106 shares and 445,114 shares, respectively, related to these obligations. During the three months ended March 31, 2014, the Company also 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").
	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 $123.5 million, a merchant banking fund of $24.4 million and private equity investment vehicles aggregating $8.3 million as of March 31, 2015. As of December 31, 2014, noncontrolling interests included the minority equity holders’ proportionate share of the equity in a municipal bond fund of $117.0 million, a merchant banking fund of $24.7 million and private equity investment vehicles aggregating $7.8 million.
	Ownership interests in entities held by parties other than the Company’s common shareholders are presented as noncontrolling interests within shareholders’ equity, separate from the Company’s own equity. Revenues, expenses and net income or loss are reported on the consolidated statements of operations on a consolidated basis, which includes amounts attributable to both the Company’s common shareholders and noncontrolling interests. Net income or loss is then allocated between the Company and noncontrolling interests based upon their relative ownership interests. Net income applicable to noncontrolling interests is deducted from consolidated net income to determine net income applicable to the Company. There was no other comprehensive income or loss attributed to noncontrolling interests for the three months ended March 31, 2015 and 2014, respectively.
		Common					Total
		Shareholders’			Noncontrolling		Shareholders’
	(Dollars in thousands)	Equity			Interests		Equity
	Balance at December 31, 2014	$	819,912		$	149,548	$	969,460
	Net income	16,972			4,830		21,802
	Amortization/issuance of restricted stock	31,884			—		31,884
	Issuance of treasury shares for options exercised	1,562			—		1,562
	Repurchase of common stock through share repurchase program	(32,720		)	—		(32,720		)
	Repurchase of common stock for employee tax withholding	(9,846		)	—		(9,846		)
	Excess tax benefit from stock-based compensation	3,662			—		3,662
	Other comprehensive loss	(475		)	—		(475		)
	Fund capital contributions, net	—			1,805		1,805
	Balance at March 31, 2015	$	830,951		$	156,183	$	987,134

Compensation_Plans

Compensation Plans	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation Plans	Compensation Plans
	Stock-Based Compensation Plans
	The Company maintains one stock-based compensation plan, the Piper Jaffray Companies Amended and Restated 2003 Annual and Long-Term Incentive Plan (the “Incentive 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 Incentive Plan equity awards (in shares or units) as of March 31, 2015:
	Restricted Stock
	Annual grants	947,122
	Sign-on grants	220,234
		1,167,356
	Restricted Stock Units
	Market condition leadership grants	405,826
	Stock Options	166,915
	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 (0.6 million shares remained available for future issuance under the Incentive Plan as of March 31, 2015). 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 also 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 2014 for its February 2015 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 grants restricted stock units to its leadership team (“Leadership Grants”). The units will vest and convert to shares of common stock at the end of each 36-month performance period only if the Company's stock performance 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's stock performance 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 was 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 2010 Employment Inducement Award Plan ("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 vested ratably over five years in equal annual installments ending on March 1, 2015. The Company terminated the Inducement Plan in March 2015.
	Stock-Based Compensation Activity
	The Company recorded total compensation expense of $13.8 million and $5.3 million for the three months ended March 31, 2015 and 2014, 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 and Leadership Grants, less forfeitures of $0.1 million for the three months ended March 31, 2015. There were no forfeitures for the three months ended March 31, 2014. The tax benefit related to stock-based compensation costs totaled $5.4 million and $2.0 million for the three months ended March 31, 2015 and 2014, respectively.
	The following table summarizes the changes in the Company’s unvested restricted stock under the Incentive Plan and Inducement Plan:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2014	1,095,305		$	36.51
	Granted	552,460		55.26
	Vested	(477,149	)	34.2
	Canceled	(3,260	)	30.61
	March 31, 2015	1,167,356		$	46.34
	The following table summarizes the changes in the Company’s unvested restricted stock units under the Incentive Plan:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2014	405,826		$	17.99
	Granted	—		—
	Vested	—		—
	Canceled	—		—
	March 31, 2015	405,826		$	17.99
	As of March 31, 2015, there was $8.7 million of total unrecognized compensation cost related to restricted stock and restricted stock units expected to be recognized over a weighted average period of 2.4 years.
	The following table summarizes the changes in the Company’s outstanding stock options:
						Weighted Average
				Weighted		Remaining
		Options		Average		Contractual Term	Aggregate
		Outstanding		Exercise Price		(in Years)	Intrinsic Value
	December 31, 2014	217,873		$	46.66	2	$	3,066,839
	Granted	—		—
	Exercised	(40,957	)	38.14
	Canceled	—		—
	Expired	(10,001	)	39.62
	March 31, 2015	166,915		$	49.17	2.3	$	1,392,298
	Options exercisable at March 31, 2015	166,915		$	49.17	2.3	$	1,392,298
As of March 31, 2015, there was no unrecognized compensation cost related to stock options expected to be recognized over future years.
The intrinsic value of options exercised was $0.7 million and the resulting tax benefit realized was $0.3 million for the three months ended March 31, 2015. The intrinsic value of options exercised and the resulting tax benefit realized were immaterial for the three months ended March 31, 2014.
Deferred Compensation Plans
The Company maintains various deferred compensation arrangements for employees.
The nonqualified deferred compensation plan is 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 $15.2 million as of March 31, 2015, 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 $15.2 million as of March 31, 2015. Changes in the fair value of the investments made by the Company are reported in investment income and changes in the corresponding deferred compensation liability are reflected as compensation and benefits expense on the consolidated statements of operations.
The Piper Jaffray Companies Mutual Fund Restricted Share Investment Plan is 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 restricted mutual fund shares ("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	3 Months Ended
	Mar. 31, 2015
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
		March 31,
	(Amounts in thousands, except per share data)	2015			2014
	Net income applicable to Piper Jaffray Companies	$	16,972		$	17,748
	Earnings allocated to participating securities (1)	(1,162		)	(1,659		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	15,810		$	16,089
	Shares for basic and diluted calculations:
	Average shares used in basic computation	15,294			14,612
	Stock options	38			45
	Average shares used in diluted computation	15,332			14,657
	Earnings per common share:
	Basic	$	1.03		$	1.1
	Diluted	$	1.03		$	1.1
	-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 1,126,906 and 1,510,839 for the three months ended March 31, 2015 and 2014, 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 three months ended March 31, 2015 and 2014.

Segment_Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2015
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. Segment assets are based on those directly associated with each segment, and include an allocation of certain assets based on the most relevant measures applicable, including headcount and other factors. The substantial majority of the Company's net revenues and long-lived assets are located in the U.S.
	Reportable segment financial results are as follows:
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Capital Markets
	Investment banking
	Financing
	Equities	$	36,489		$	35,301
	Debt	21,738			13,539
	Advisory services	29,266			39,728
	Total investment banking	87,493			88,568
	Institutional sales and trading
	Equities	18,905			24,260
	Fixed income	21,217			25,238
	Total institutional sales and trading	40,122			49,498
	Management and performance fees	1,407			1,737
	Investment income	14,705			10,378
	Long-term financing expenses	(1,560		)	(1,740		)
	Net revenues	142,167			148,441
	Operating expenses (1)	116,203			120,930
	Segment pre-tax operating income	$	25,964		$	27,511
	Segment pre-tax operating margin	18.3		%	18.5		%
	Continued on next page
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Asset Management
	Management and performance fees
	Management fees	$	19,107		$	19,136
	Performance fees	8			86
	Total management and performance fees	19,115			19,222
	Investment income	589			470
	Net revenues	19,704			19,692
	Operating expenses (1)	14,376			14,490
	Segment pre-tax operating income	$	5,328		$	5,202
	Segment pre-tax operating margin	27		%	26.4		%
	Total
	Net revenues	$	161,871		$	168,133
	Operating expenses (1)	130,579			135,420
	Pre-tax operating income	$	31,292		$	32,713
	Pre-tax operating margin	19.3		%	19.5		%
	(1)Operating expenses include intangible asset amortization expense as set forth in the table below:
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Capital Markets	$	263		$	743
	Asset Management	1,510			1,575
	Total intangible asset amortization expense	$	1,773		$	2,318
	Reportable segment assets are as follows:
		March 31,			December 31,
	(Dollars in thousands)	2015			2014
	Capital Markets	$	2,656,313		$	2,352,404
	Asset Management	260,716			271,513
		$	2,917,029		$	2,623,917

Net_Capital_Requirements_and_O

Net Capital Requirements and Other Regulatory Matters	3 Months Ended
	Mar. 31, 2015
Regulatory Capital Requirements [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 March 31, 2015, net capital calculated under the SEC rule was $148.9 million, and exceeded the minimum net capital required under the SEC rule by $147.9 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 March 31, 2015, Piper Jaffray Ltd. was in compliance with the capital requirements of the Prudential Regulation Authority and the Financial Conduct Authority.

Financial_Instruments_and_Othe1

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased (Tables)	3 Months Ended
	Mar. 31, 2015
Securities Owned and Sold, 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:
		March 31,				December 31,
	(Dollars in thousands)	2015				2014
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Equity securities	$	60,806			$	50,365
	Convertible securities	167,169				156,685
	Fixed income securities	30,702				48,651
	Municipal securities:
	Taxable securities	271,821				312,753
	Tax-exempt securities	597,299				559,704
	Short-term securities	87,581				68,717
	Asset-backed securities	148,957				125,065
	U.S. government agency securities	333,053				244,046
	U.S. government securities	826				2,549
	Derivative contracts	48,953				47,826
	Total financial instruments and other inventory positions owned	1,747,167				1,616,361
	Less noncontrolling interests (1)	(305,932		)		(267,742		)
		$	1,441,235			$	1,348,619
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	158,297			$	154,589
	Convertible securities	269				—
	Fixed income securities	30,293				21,460
	U.S. government agency securities	20,225				27,735
	U.S. government securities	558,477				523,527
	Derivative contracts	10,707				10,813
	Total financial instruments and other inventory positions sold, but not yet purchased	778,268				738,124
	Less noncontrolling interests (2)	(94,831		)		(98,669		)
		$	683,437			$	639,455
	-1	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $111.6 million and $123.3 million of taxable municipal securities, $188.9 million and $139.5 million of tax-exempt municipal securities, and $5.4 million and $4.9 million of derivative contracts as of March 31, 2015 and December 31, 2014, respectively.
	-2	Noncontrolling interests attributable to third party ownership in a consolidated municipal bond fund consist of $93.7 million and $97.6 million of U.S. government securities, and $1.1 million of derivative contracts as of March 31, 2015 and December 31, 2014
Total Absolute Notional Contract Amount	The following table presents the gross fair market value and the total absolute notional contract amount of the Company's outstanding derivative instruments, prior to counterparty netting, by asset or liability position:
			March 31, 2015										December 31, 2014
	(Dollars in thousands)		Derivative				Derivative				Notional		Derivative		Derivative		Notional
	Derivative Category		Assets (1)				Liabilities (2)				Amount		Assets (1)		Liabilities (2)		Amount
	Interest rate
	Customer matched-book		$	486,922			$	464,143			$	4,838,143	$	447,987	$	425,227	$	4,860,302
	Trading securities		1,222				9,184				411,750		140		8,242		297,250
	Credit default swap index
	Trading securities		5,769				6,358				247,721		5,808		5,188		267,796
	Equity option
	Trading securities		156				147				49,585		76		189		19,380
			$	494,069			$	479,832			$	5,547,199	$	454,011	$	438,846	$	5,444,728
Unrealized Gains/(Losses) on Derivative Instruments	The following table presents the Company’s unrealized gains/(losses) on derivative instruments:
					Three Months Ended
	(Dollars in thousands)				March 31,
	Derivative Category		Operations Category		2015				2014
	Interest rate derivative contract		Investment banking		$	(520	)		$	(524	)
	Interest rate derivative contract		Institutional brokerage		679				532
	Credit default swap index contract		Institutional brokerage		4,607				(1,254		)
	Equity option derivative contract		Institutional brokerage		35				948
					$	4,801			$	(298	)

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
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 March 31, 2015:
		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 - 60%		19.40%
	Short-term securities	Discounted cash flow		Expected recovery rate (% of par) (2)	66 - 94%		91.00%
	Asset-backed securities:
	Collateralized by residential mortgages	Discounted cash flow		Credit default rates (3)	1 - 5%		3.20%
				Prepayment rates (4)	0 - 26%		5.50%
				Loss severity (3)	32 - 90%		58.20%
				Valuation yields (3)	2 - 8%		4.80%
	Derivative contracts:
	Interest rate locks	Discounted cash flow		Premium over the MMD curve (1)	4 - 23 bps		8.6 bps
	Investments at fair value:
	Warrants in public and private companies	Black-Scholes option pricing model		Liquidity discount rates (1)	30 - 40%		39.30%
	Warrants in private companies	Black-Scholes option pricing model		Stock volatility factors of comparable companies (2)	29 - 57%		42.00%
	Equity securities in private companies	Market approach		Revenue multiple (2)	2 - 6 times		4.6 times
				EBITDA multiple (2)	9 - 12 times		9.7 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)	0 - 26 bps		6.0 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 March 31, 2015:
											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	$	48,372		$	12,434		$	—		$	—		$	60,806
	Convertible securities	—			167,169			—			—			167,169
	Fixed income securities	—			30,702			—			—			30,702
	Municipal securities:
	Taxable securities	—			271,821			—			—			271,821
	Tax-exempt securities	—			596,123			1,176			—			597,299
	Short-term securities	—			86,861			720			—			87,581
	Asset-backed securities	—			1,080			147,877			—			148,957
	U.S. government agency securities	—			333,053			—			—			333,053
	U.S. government securities	826			—			—			—			826
	Derivative contracts	156			492,691			1,222			(445,116		)	48,953
	Total financial instruments and other inventory positions owned:	49,354			1,991,934			150,995			(445,116		)	1,747,167
	Cash equivalents	865			—			—			—			865
	Investments at fair value	29,613			—			87,468			—			117,081
	Total assets	$	79,832		$	1,991,934		$	238,463		$	(445,116	)	$	1,865,113
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	155,331		$	2,966		$	—		$	—		$	158,297
	Convertible securities	—			269			—			—			269
	Fixed income securities	—			30,293			—			—			30,293
	U.S. government agency securities	—			20,225			—			—			20,225
	U.S. government securities	558,477			—			—			—			558,477
	Derivative contracts	147			471,459			8,226			(469,125		)	10,707
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	713,955		$	525,212		$	8,226		$	(469,125	)	$	778,268
	-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, 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	$	39,191		$	11,174		$	—		$	—		$	50,365
	Convertible securities	—			156,685			—			—			156,685
	Fixed income securities	—			48,651			—			—			48,651
	Municipal securities:
	Taxable securities	—			312,753			—			—			312,753
	Tax-exempt securities	—			558,518			1,186			—			559,704
	Short-term securities	—			67,997			720			—			68,717
	Asset-backed securities	—			316			124,749			—			125,065
	U.S. government agency securities	—			244,046			—			—			244,046
	U.S. government securities	2,549			—			—			—			2,549
	Derivative contracts	76			453,795			140			(406,185		)	47,826
	Total financial instruments and other inventory positions owned:	41,816			1,853,935			126,795			(406,185		)	1,616,361
	Cash equivalents	1,562			—			—			—			1,562
	Investments at fair value	20,704			—			74,165			—			94,869
	Total assets	$	64,082		$	1,853,935		$	200,960		$	(406,185	)	$	1,712,792
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Corporate securities:
	Equity securities	$	153,254		$	1,335		$	—		$	—		$	154,589
	Fixed income securities	—			21,460			—			—			21,460
	U.S. government agency securities	—			27,735			—			—			27,735
	U.S. government securities	523,527			—			—			—			523,527
Derivative contracts	189			430,835			7,822			(428,033		)	10,813
Total financial instruments and other inventory positions sold, but not yet purchased:	$	676,970		$	481,365		$	7,822		$	(428,033	)	$	738,124
-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:
																								Unrealized gains/
																								(losses) for assets/
		Balance at														Realized			Unrealized			Balance at		liabilities held at
		December 31,									Transfers			Transfers		gains/			gains/			March 31,		March 31,
	(Dollars in thousands)	2014			Purchases			Sales			in			out		(losses) (1)			(losses) (1)			2015		2015 (1)
	Assets:
	Financial instruments and other inventory positions owned:
	Municipal securities:
	Tax-exempt securities	$	1,186		$	—		$	—		$	—		$	—	$	—		$	(10	)	$	1,176	$	(10	)
	Short-term securities	720			—			—			—			—		—			—			720		—
	Asset-backed securities	124,749			119,826			(98,947		)	—			—		2,490			(241		)	147,877		517
	Derivative contracts	140			520			—			—			—		(520		)	1,082			1,222		1,222
	Total financial instruments and other inventory positions owned:	126,795			120,346			(98,947		)	—			—		1,970			831			150,995		1,729
	Investments at fair value	74,165			—			(182		)	—			—		182			13,303			87,468		13,303
	Total assets	$	200,960		$	120,346		$	(99,129	)	$	—		$	—	$	2,152		$	14,134		$	238,463	$	15,032
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts	$	7,822		$	(5,814	)	$	—		$	—		$	—	$	5,814		$	404		$	8,226	$	4,318
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	7,822		$	(5,814	)	$	—		$	—		$	—	$	5,814		$	404		$	8,226	$	4,318
	-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 on the consolidated statements of operations.
																								Unrealized gains/
																								(losses) for assets/
		Balance at														Realized			Unrealized			Balance at		liabilities held at
		December 31,									Transfers			Transfers		gains/			gains/			March 31,		March 31,
	(Dollars in thousands)	2013			Purchases			Sales			in			out		(losses) (1)			(losses) (1)			2014		2014 (1)
	Assets:
	Financial instruments and other inventory positions owned:
	Corporate securities:
	Fixed income securities	$	100		$	—		$	—		$	—		$	—	$	—		$	—		$	100	$	—
	Municipal securities:
	Tax-exempt securities	1,433			—			—			—			—		—			—			1,433		—
	Short-term securities	656			—			—			—			—		—			—			656		—
	Asset-backed securities	119,799			96,725			(114,506		)	—			—		6,270			(889		)	107,399		958
	Derivative contracts	691			2,614			—			—			—		(2,614		)	(627		)	64		64
	Total financial instruments and other inventory positions owned:	122,679			99,339			(114,506		)	—			—		3,656			(1,516		)	109,652		1,022
	Investments at fair value	49,240			10,000			—			—			—		—			1,714			60,954		1,714
	Total assets	$	171,919		$	109,339		$	(114,506	)	$	—		$	—	$	3,656		$	198		$	170,606	$	2,736
	Liabilities:
	Financial instruments and other inventory positions sold, but not yet purchased:
	Derivative contracts	$	6,643		$	(16,751	)	$	—		$	—		$	—	$	16,751		$	(1,164	)	$	5,479	$	5,479
	Total financial instruments and other inventory positions sold, but not yet purchased:	$	6,643		$	(16,751	)	$	—		$	—		$	—	$	16,751		$	(1,164	)	$	5,479	$	5,479
	-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 on the consolidated statements of operations.

Receivables_from_and_Payables_1

Receivables from and Payables to Brokers, Dealers and Clearing Organizations (Tables)	3 Months Ended
	Mar. 31, 2015
Brokers and Dealers [Abstract]
Brokers, Dealers and Clearing Organizations	Amounts receivable from brokers, dealers and clearing organizations included:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Receivable arising from unsettled securities transactions	$	49,725	$	52,571
	Deposits paid for securities borrowed	49,317		57,572
	Receivable from clearing organizations	11,203		4,933
	Deposits with clearing organizations	64,918		33,799
	Securities failed to deliver	7,254		1,753
	Other	19,795		10,381
		$	202,212	$	161,009
	Amounts payable to brokers, dealers and clearing organizations included:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Payable arising from unsettled securities transactions	$	148,353	$	11,048
	Payable to clearing organizations	9,204		5,185
	Securities failed to receive	7,394		2,430
	Other	11,503		6,901
		$	176,454	$	25,564

Collateralized_Securities_Tran1

Collateralized Securities Transactions (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Repurchase Agreements [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 March 31, 2015:
		Repurchase		Fair Market
	(Dollars in thousands)	Liabilities		Value		Interest Rate
	Term up to 30 day maturities:
	Asset-backed securities	$	19,860	$	31,042	1.67 - 1.93%
	Term of 30 to 90 day maturities:
	Asset-backed securities	4,637		6,624		2.02%
	On demand maturities:
	Corporate securities:
	Fixed income securities	8,671		8,971		0.80%
	U.S. government agency securities	126,104		143,976		0.55 - 0.85%
	U.S. government securities	9,955		9,979		0.40%
		$	169,227	$	200,592

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, All Other 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:
		March 31,			December 31,
	(Dollars in thousands)	2015			2014
	Investments at fair value	$	117,081		$	94,869
	Investments at cost	3,805			8,214
	Investments accounted for under the equity method	24,024			23,757
	Total investments	144,910			126,840
	Less investments attributable to noncontrolling interests (1)	(32,710		)	(32,563		)
		$	112,200		$	94,277
	-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)	3 Months Ended
	Mar. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other assets included:
		March 31,		December 31,
	(Dollars in thousands)	2015		2014
	Net deferred income tax assets	$	35,689	$	45,851
	Fee receivables	26,211		23,959
	Accrued interest receivables	10,560		10,061
	Forgivable loans, net	9,685		8,366
	Income tax receivables	17,792		—
	Prepaid expenses	5,215		6,067
	Other	9,412		5,995
	Total other assets	$	114,564	$	100,299

ShortTerm_Financing_Tables

Short-Term Financing (Tables)	3 Months Ended
	Mar. 31, 2015
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
		March 31,		December 31,		March 31,	December 31,
	(Dollars in thousands)	2015		2014		2015	2014
	Commercial paper (secured)	$	245,994	$	238,013	1.52%	1.48%
	Prime broker arrangement	220,528		127,754		0.93%	0.91%
	Bank lines (secured)	51,000		12,000		1.11%	1.50%
	Total short-term financing	$	517,522	$	377,767

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table Text Block]	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 three months ended March 31, 2015 and 2014, respectively.
		Common					Total
		Shareholders’			Noncontrolling		Shareholders’
	(Dollars in thousands)	Equity			Interests		Equity
	Balance at December 31, 2014	$	819,912		$	149,548	$	969,460
	Net income	16,972			4,830		21,802
	Amortization/issuance of restricted stock	31,884			—		31,884
	Issuance of treasury shares for options exercised	1,562			—		1,562
	Repurchase of common stock through share repurchase program	(32,720		)	—		(32,720		)
	Repurchase of common stock for employee tax withholding	(9,846		)	—		(9,846		)
	Excess tax benefit from stock-based compensation	3,662			—		3,662
	Other comprehensive loss	(475		)	—		(475		)
	Fund capital contributions, net	—			1,805		1,805
	Balance at March 31, 2015	$	830,951		$	156,183	$	987,134

Compensation_Plans_Tables

Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2015
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 Incentive Plan equity awards (in shares or units) as of March 31, 2015:
	Restricted Stock
	Annual grants	947,122
	Sign-on grants	220,234
		1,167,356
	Restricted Stock Units
	Market condition leadership grants	405,826
	Stock Options	166,915
Schedule of Valuation Assumptions	The fair value of the awards on the grant date was 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 under the Incentive Plan and Inducement Plan:
		Unvested		Weighted Average
		Restricted Stock		Grant Date
		(in Shares)		Fair Value
	December 31, 2014	1,095,305		$	36.51
	Granted	552,460		55.26
	Vested	(477,149	)	34.2
	Canceled	(3,260	)	30.61
	March 31, 2015	1,167,356		$	46.34
Changes in Unvested Restricted Stock Units	The following table summarizes the changes in the Company’s unvested restricted stock units under the Incentive Plan:
		Unvested		Weighted Average
		Restricted		Grant Date
		Stock Units		Fair Value
	December 31, 2014	405,826		$	17.99
	Granted	—		—
	Vested	—		—
	Canceled	—		—
	March 31, 2015	405,826		$	17.99
Changes in Outstanding Stock Options	The following table summarizes the changes in the Company’s outstanding stock options:
						Weighted Average
				Weighted		Remaining
		Options		Average		Contractual Term	Aggregate
		Outstanding		Exercise Price		(in Years)	Intrinsic Value
	December 31, 2014	217,873		$	46.66	2	$	3,066,839
	Granted	—		—
	Exercised	(40,957	)	38.14
	Canceled	—		—
	Expired	(10,001	)	39.62
	March 31, 2015	166,915		$	49.17	2.3	$	1,392,298
	Options exercisable at March 31, 2015	166,915		$	49.17	2.3	$	1,392,298

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Computation of Earnings per Share	The computation of earnings per share is as follows:
		Three Months Ended
		March 31,
	(Amounts in thousands, except per share data)	2015			2014
	Net income applicable to Piper Jaffray Companies	$	16,972		$	17,748
	Earnings allocated to participating securities (1)	(1,162		)	(1,659		)
	Net income applicable to Piper Jaffray Companies’ common shareholders (2)	$	15,810		$	16,089
	Shares for basic and diluted calculations:
	Average shares used in basic computation	15,294			14,612
	Stock options	38			45
	Average shares used in diluted computation	15,332			14,657
	Earnings per common share:
	Basic	$	1.03		$	1.1
	Diluted	$	1.03		$	1.1
	-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 1,126,906 and 1,510,839 for the three months ended March 31, 2015 and 2014, 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)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Reportable segment financial results	Reportable segment financial results are as follows:
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Capital Markets
	Investment banking
	Financing
	Equities	$	36,489		$	35,301
	Debt	21,738			13,539
	Advisory services	29,266			39,728
	Total investment banking	87,493			88,568
	Institutional sales and trading
	Equities	18,905			24,260
	Fixed income	21,217			25,238
	Total institutional sales and trading	40,122			49,498
	Management and performance fees	1,407			1,737
	Investment income	14,705			10,378
	Long-term financing expenses	(1,560		)	(1,740		)
	Net revenues	142,167			148,441
	Operating expenses (1)	116,203			120,930
	Segment pre-tax operating income	$	25,964		$	27,511
	Segment pre-tax operating margin	18.3		%	18.5		%
	Continued on next page
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Asset Management
	Management and performance fees
	Management fees	$	19,107		$	19,136
	Performance fees	8			86
	Total management and performance fees	19,115			19,222
	Investment income	589			470
	Net revenues	19,704			19,692
	Operating expenses (1)	14,376			14,490
	Segment pre-tax operating income	$	5,328		$	5,202
	Segment pre-tax operating margin	27		%	26.4		%
	Total
	Net revenues	$	161,871		$	168,133
	Operating expenses (1)	130,579			135,420
	Pre-tax operating income	$	31,292		$	32,713
	Pre-tax operating margin	19.3		%	19.5		%
	(1)Operating expenses include intangible asset amortization expense as set forth in the table below:
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Capital Markets	$	263		$	743
	Asset Management	1,510			1,575
	Total intangible asset amortization expense	$	1,773		$	2,318
Schedule of intangible asset amortization expense	Operating expenses include intangible asset amortization expense as set forth in the table below:
		Three Months Ended
		March 31,
	(Dollars in thousands)	2015			2014
	Capital Markets	$	263		$	743
	Asset Management	1,510			1,575
	Total intangible asset amortization expense	$	1,773		$	2,318
Reportable segment assets	Reportable segment assets are as follows:
		March 31,			December 31,
	(Dollars in thousands)	2015			2014
	Capital Markets	$	2,656,313		$	2,352,404
	Asset Management	260,716			271,513
		$	2,917,029		$	2,623,917

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015
	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	2

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 $)	Mar. 31, 2015	Dec. 31, 2014
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	$1,747,167	$1,616,361
Financial instruments and other inventory positions sold, but not yet purchased	778,268	738,124
Financial instruments and other inventory positions owned and pledged as collateral	1,211,706	1,108,567
Equity securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	60,806	50,365
Financial instruments and other inventory positions sold, but not yet purchased	158,297	154,589
Convertible securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	167,169	156,685
Financial instruments and other inventory positions sold, but not yet purchased	269	0
Fixed income securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	30,702	48,651
Financial instruments and other inventory positions sold, but not yet purchased	30,293	21,460
Taxable securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	271,821	312,753
Tax-exempt securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	597,299	559,704
Short-term securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	87,581	68,717
Asset-backed securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	148,957	125,065
U.S. government agency securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	333,053	244,046
Financial instruments and other inventory positions sold, but not yet purchased	20,225	27,735
U.S. government securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	826	2,549
Financial instruments and other inventory positions sold, but not yet purchased	558,477	523,527
Derivative contracts
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	48,953	47,826
Financial instruments and other inventory positions sold, but not yet purchased	10,707	10,813
Municipal Bond Fund
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	305,932	267,742
Financial instruments and other inventory positions sold, but not yet purchased	94,831	98,669
Municipal Bond Fund | Taxable securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	111,600	123,300
Municipal Bond Fund | Tax-exempt securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	188,900	139,500
Municipal Bond Fund | U.S. government securities
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Financial instruments and other inventory positions sold, but not yet purchased	93,700	97,600
Municipal Bond Fund | Derivative contracts
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	5,400	4,900
Financial instruments and other inventory positions sold, but not yet purchased	1,100	1,100
Parent Company
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Total financial instruments and other inventory positions owned	1,441,235	1,348,619
Financial instruments and other inventory positions sold, but not yet purchased	$683,437	$639,455

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) (Not Designated as Hedging Instrument, USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivative [Line Items]
Derivative Assets (1)	$494,069	$454,011
Derivative Liabilities (2)	479,832	438,846
Notional Amount	5,547,199	5,444,728
Interest rate | Customer matched-book
Derivative [Line Items]
Notional Amount	4,838,143	4,860,302
Interest rate | Customer matched-book | Financial instruments and other inventory positions owned
Derivative [Line Items]
Derivative Assets (1)	486,922	447,987
Interest rate | Customer matched-book | Financial instruments and other inventory positions sold, but not yet purchased
Derivative [Line Items]
Derivative Liabilities (2)	464,143	425,227
Interest rate | Trading securities
Derivative [Line Items]
Notional Amount	411,750	297,250
Interest rate | Trading securities | Financial instruments and other inventory positions owned
Derivative [Line Items]
Derivative Assets (1)	1,222	140
Interest rate | Trading securities | Financial instruments and other inventory positions sold, but not yet purchased
Derivative [Line Items]
Derivative Liabilities (2)	9,184	8,242
Credit default swap index | Trading securities
Derivative [Line Items]
Notional Amount	247,721	267,796
Credit default swap index | Trading securities | Financial instruments and other inventory positions owned
Derivative [Line Items]
Derivative Assets (1)	5,769	5,808
Credit default swap index | Trading securities | Financial instruments and other inventory positions sold, but not yet purchased
Derivative [Line Items]
Derivative Liabilities (2)	6,358	5,188
Equity option | Trading securities
Derivative [Line Items]
Notional Amount	49,585	19,380
Equity option | Trading securities | Financial instruments and other inventory positions owned
Derivative [Line Items]
Derivative Assets (1)	156	76
Equity option | Trading securities | Financial instruments and other inventory positions sold, but not yet purchased
Derivative [Line Items]
Derivative Liabilities (2)	$147	$189

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) (Not Designated as Hedging Instrument, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives Instruments	$4,801	($298)
Interest rate derivative contract | Investment banking
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives Instruments	-520	-524
Interest rate derivative contract | Institutional brokerage
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives Instruments	679	532
Credit default swap index contract | Institutional brokerage
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives Instruments	4,607	-1,254
Equity option derivative contract | Institutional brokerage
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives Instruments	$35	$948

Financial_Instruments_and_Othe5

Financial Instruments and Other Inventory Positions Owned and Financial Instruments and Other Inventory Positions Sold, but Not Yet Purchased - Additional Information (Details) (Maximum risk of loss, USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Counterparties not required to post collateral
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Uncollateralized credit exposure	$27.60
Notional contract amount	189
One unnamed financial institutional not required to post collateral
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Uncollateralized credit exposure	$18.40

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments Fair Value of Financial Instruments - Fair Value Option (Details) (Level III, USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Investments at fair value	$87,468,000		$74,165,000
Merchant Banking Investments
Fair Value, Option, Quantitative Disclosures [Line Items]
Investments at fair value	19,300,000		18,400,000
Gains from changes in fair value	$800,000	$300,000

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Information about Significant Unobservable Inputs used in Fair Value Measurement (Details) (Level III)	3 Months Ended
	Mar. 31, 2015
Financial instruments and other inventory positions sold, but not yet purchased | Minimum | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.00%
Financial instruments and other inventory positions sold, but not yet purchased | Maximum | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.26%
Financial instruments and other inventory positions sold, but not yet purchased | Weighted Average | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.06%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Tax-exempt securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Debt service coverage ratio	5.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Short-term securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Expected recovery rate (% of par)	66.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Collateralized by residential mortgages
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Credit default rate	1.00%
Prepayment rates	0.00%
Loss severity	32.00%
Valuation yields	2.00%
Financial instruments and other inventory positions owned | Minimum | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.04%
Financial instruments and other inventory positions owned | Minimum | Black-Scholes option pricing model | Warrants in public and private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Liquidity discount rates	30.00%
Financial instruments and other inventory positions owned | Minimum | Black-Scholes option pricing model | Warrants in private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Stock volatility factors of comparable companies	29.30%
Financial instruments and other inventory positions owned | Minimum | Market approach | Equity investment in private company
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Revenue multiple	1.9
EBITDA multiple	8.8
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Tax-exempt securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Debt service coverage ratio	60.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Short-term securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Expected recovery rate (% of par)	94.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Collateralized by residential mortgages
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Credit default rate	5.00%
Prepayment rates	26.00%
Loss severity	90.00%
Valuation yields	8.00%
Financial instruments and other inventory positions owned | Maximum | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.23%
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Warrants in public and private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Liquidity discount rates	40.00%
Financial instruments and other inventory positions owned | Maximum | Black-Scholes option pricing model | Warrants in private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Stock volatility factors of comparable companies	56.90%
Financial instruments and other inventory positions owned | Maximum | Market approach | Equity investment in private company
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Revenue multiple	6
EBITDA multiple	12
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Tax-exempt securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Debt service coverage ratio	19.40%
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Short-term securities
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Expected recovery rate (% of par)	91.00%
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Collateralized by residential mortgages
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Credit default rate	3.20%
Prepayment rates	5.45%
Loss severity	58.22%
Valuation yields	4.78%
Financial instruments and other inventory positions owned | Weighted Average | Discounted cash flow | Interest rate locks
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Unamortized premium over the MMD curve	0.09%
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Warrants in public and private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Liquidity discount rates	39.30%
Financial instruments and other inventory positions owned | Weighted Average | Black-Scholes option pricing model | Warrants in private companies
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Stock volatility factors of comparable companies	42.00%
Financial instruments and other inventory positions owned | Weighted Average | Market approach | Equity investment in private company
Fair Value Inputs Assets and Liabilities Quantitative Information [Line Items]
Revenue multiple	4.6
EBITDA multiple	9.7

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers between fair value levels	$0
Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	1,991,934,000	1,853,935,000
Level III
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	$238,463,000	$200,960,000
Percentage of Level III assets to financial instruments measured at fair value	12.80%	11.70%
U.S. government agency securities | Minimum | Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Market yields basis points spreads to treasury securities (as a percent)	0.50%
Prepayment expectations based upon PSA prepayment levels	50
U.S. government agency securities | Maximum | Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Market yields basis points spreads to treasury securities (as a percent)	10.68%
Prepayment expectations based upon PSA prepayment levels	490

Fair_Value_of_Financial_Instru5

Fair Value of Financial Instruments - Valuation of Financial Instruments by Pricing Observability Levels (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	$1,747,167	$1,616,361
Derivative contracts	-445,116	-406,185
Financial instruments and other inventory positions sold, but not yet purchased	778,268	738,124
Derivative contracts	-469,125	-428,033
Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	60,806	50,365
Financial instruments and other inventory positions sold, but not yet purchased	158,297	154,589
Convertible securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	167,169	156,685
Financial instruments and other inventory positions sold, but not yet purchased	269	0
Fixed income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	30,702	48,651
Financial instruments and other inventory positions sold, but not yet purchased	30,293	21,460
Taxable securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	271,821	312,753
Tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	597,299	559,704
Short-term securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	87,581	68,717
Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	148,957	125,065
U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	333,053	244,046
Financial instruments and other inventory positions sold, but not yet purchased	20,225	27,735
U.S. government securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	826	2,549
Financial instruments and other inventory positions sold, but not yet purchased	558,477	523,527
Derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	48,953	47,826
Derivative contracts	-445,116	-406,185
Financial instruments and other inventory positions sold, but not yet purchased	10,707	10,813
Derivative contracts	-469,125	-428,033
Level I
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	49,354	41,816
Cash equivalents	865	1,562
Investments at fair value	29,613	20,704
Total assets	79,832	64,082
Financial instruments and other inventory positions sold, but not yet purchased	713,955	676,970
Level I | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	48,372	39,191
Financial instruments and other inventory positions sold, but not yet purchased	155,331	153,254
Level I | U.S. government securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	826	2,549
Financial instruments and other inventory positions sold, but not yet purchased	558,477	523,527
Level I | Derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	156	76
Financial instruments and other inventory positions sold, but not yet purchased	147	189
Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	1,991,934	1,853,935
Total assets	1,991,934	1,853,935
Financial instruments and other inventory positions sold, but not yet purchased	525,212	481,365
Level II | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	12,434	11,174
Financial instruments and other inventory positions sold, but not yet purchased	2,966	1,335
Level II | Convertible securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	167,169	156,685
Financial instruments and other inventory positions sold, but not yet purchased	269
Level II | Fixed income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	30,702	48,651
Financial instruments and other inventory positions sold, but not yet purchased	30,293	21,460
Level II | Taxable securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	271,821	312,753
Level II | Tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	596,123	558,518
Level II | Short-term securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	86,861	67,997
Level II | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	1,080	316
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	333,053	244,046
Financial instruments and other inventory positions sold, but not yet purchased	20,225	27,735
Level II | Derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	492,691	453,795
Financial instruments and other inventory positions sold, but not yet purchased	471,459	430,835
Level III
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	150,995	126,795
Investments at fair value	87,468	74,165
Total assets	238,463	200,960
Financial instruments and other inventory positions sold, but not yet purchased	8,226	7,822
Level III | Tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	1,176	1,186
Level III | Short-term securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	720	720
Level III | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	147,877	124,749
Level III | Derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	1,222	140
Financial instruments and other inventory positions sold, but not yet purchased	8,226	7,822
Measured on a recurring basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	1,747,167	1,616,361
Cash equivalents	865	1,562
Investments at fair value	117,081	94,869
Total assets	1,865,113	1,712,792
Financial instruments and other inventory positions sold, but not yet purchased	778,268	738,124
Measured on a recurring basis | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	60,806	50,365
Financial instruments and other inventory positions sold, but not yet purchased	158,297	154,589
Measured on a recurring basis | Convertible securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	167,169	156,685
Financial instruments and other inventory positions sold, but not yet purchased	269
Measured on a recurring basis | Fixed income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	30,702	48,651
Financial instruments and other inventory positions sold, but not yet purchased	30,293	21,460
Measured on a recurring basis | Taxable securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	271,821	312,753
Measured on a recurring basis | Tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	597,299	559,704
Measured on a recurring basis | Short-term securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	87,581	68,717
Measured on a recurring basis | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	148,957	125,065
Measured on a recurring basis | U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	333,053	244,046
Financial instruments and other inventory positions sold, but not yet purchased	20,225	27,735
Measured on a recurring basis | U.S. government securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	826	2,549
Financial instruments and other inventory positions sold, but not yet purchased	558,477	523,527
Measured on a recurring basis | Derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial instruments and other inventory positions owned	48,953	47,826
Financial instruments and other inventory positions sold, but not yet purchased	$10,707	$10,813

Fair_Value_of_Financial_Instru6

Fair Value of Financial Instruments - Changes in Fair Value Associated with Level III Financial Instruments (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$200,960	$171,919
Purchases	120,346	109,339
Sales	-99,129	-114,506
Realized gains/ (losses)	-2,152	-3,656
Unrealized gains/ (losses)	-14,134	-198
Ending balance	238,463	170,606
Unrealized gains/ (losses) for assets held at period end	-15,032	-2,736
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7,822	6,643
Purchases	-5,814	-16,751
Realized gains/(losses)	5,814	16,751
Unrealized gains/ (losses)	-404	-1,164
Ending balance	8,226	5,479
Unrealized gains/ (losses) for liabilities held at period end	4,318	5,479
Financial instruments and other inventory positions sold, but not yet purchased | Derivative contracts
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7,822	6,643
Purchases	-5,814	-16,751
Realized gains/(losses)	5,814	16,751
Unrealized gains/ (losses)	-404	-1,164
Ending balance	8,226	5,479
Unrealized gains/ (losses) for liabilities held at period end	4,318	5,479
Financial instruments and other inventory positions owned
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	126,795	122,679
Purchases	120,346	99,339
Sales	-98,947	-114,506
Realized gains/ (losses)	-1,970	-3,656
Unrealized gains/ (losses)	-831	-1,516
Ending balance	150,995	109,652
Unrealized gains/ (losses) for assets held at period end	-1,729	-1,022
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
Ending balance		100
Unrealized gains/ (losses) for assets held at period end		0
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	1,186		1,433
Unrealized gains/ (losses)	-10
Ending balance	1,176	1,433	1,433
Unrealized gains/ (losses) for assets held at period end	-10
Financial instruments and other inventory positions owned | Short-term securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance			656	720
Ending balance	720	656	656	720
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	124,749	119,799
Purchases	119,826	96,725
Sales	-98,947	-114,506
Realized gains/ (losses)	-2,490	-6,270
Unrealized gains/ (losses)	-241	-889
Ending balance	147,877	107,399
Unrealized gains/ (losses) for assets held at period end	-517	-958
Financial instruments and other inventory positions owned | Derivative contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	140	691
Purchases	520	2,614
Realized gains/ (losses)	-520	-2,614
Unrealized gains/ (losses)	-1,082	-627
Ending balance	1,222	64
Unrealized gains/ (losses) for assets held at period end	-1,222	-64
Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	74,165	49,240
Purchases		10,000
Sales	-182
Realized gains/ (losses)	-182
Unrealized gains/ (losses)	-13,303	-1,714
Ending balance	87,468	60,954
Unrealized gains/ (losses) for assets held at period end	($13,303)	($1,714)

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 $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Brokers and Dealers [Abstract]
Receivable arising from unsettled securities transactions	$49,725	$52,571
Deposits paid for securities borrowed	49,317	57,572
Receivable from clearing organizations	11,203	4,933
Deposits with clearing organizations	64,918	33,799
Securities failed to deliver	7,254	1,753
Other	19,795	10,381
Brokers, dealers and clearing organizations	$202,212	$161,009

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 $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Brokers and Dealers [Abstract]
Payable arising from unsettled securities transactions	$148,353	$11,048
Payable to clearing organizations	9,204	5,185
Securities failed to receive	7,394	2,430
Other	11,503	6,901
Brokers, dealers and clearing organizations	$176,454	$25,564

Collateralized_Securities_Tran2

Collateralized Securities Transactions - Summary of Repurchase Liabilities, Fair Market Value of Related Collateral Pledged and Interest Rate Charged (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	$169,227
Fair Market Value	200,592
Maturity up to 30 days | Asset-backed securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	19,860
Fair Market Value	31,042
Maturity up to 30 days | Asset-backed securities | Minimum
Assets Sold under Agreements to Repurchase [Line Items]
Interest Rate	1.67%
Maturity up to 30 days | Asset-backed securities | Maximum
Assets Sold under Agreements to Repurchase [Line Items]
Interest Rate	1.93%
Maturity 30 to 90 Days | Asset-backed securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	4,637
Fair Market Value	6,624
Interest Rate	2.02%
On demand maturities | Fixed income securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	8,671
Fair Market Value	8,971
Interest Rate	0.80%
On demand maturities | U.S. government agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	126,104
Fair Market Value	143,976
On demand maturities | U.S. government agency securities | Minimum
Assets Sold under Agreements to Repurchase [Line Items]
Interest Rate	0.55%
On demand maturities | U.S. government agency securities | Maximum
Assets Sold under Agreements to Repurchase [Line Items]
Interest Rate	0.85%
On demand maturities | U.S. government securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Liabilities	9,955
Fair Market Value	$9,979
Interest Rate	0.40%

Collateralized_Securities_Tran3

Collateralized Securities Transactions - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Disclosure of Repurchase Agreements [Abstract]
Securities purchased under agreements to resell, securities borrowed and margin agreements on terms that permit to repledge or resell the securities to others	$440,000,000	$369,700,000
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	428,200,000	338,800,000
Reverse Repurchase, Offset Value	0	0
Securities loaned	$0	$0

Investments_Details

Investments (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investments, All Other Investments [Abstract]
Investments at fair value	$117,081	$94,869
Investments at cost	3,805	8,214
Investments accounted for under the equity method	24,024	23,757
Total investments	144,910	126,840
Less investments attributable to noncontrolling interests	-32,710	-32,563
Investments less portion attributable to noncontolling interest	$112,200	$94,277

Investments_Additional_Informa

Investments - Additional Information (Details) (USD $)	Mar. 31, 2015
Investment [Line Items]
Estimated fair market value of investments carried at cost	$9,400,000
Debt investment in private company [Member]
Investment [Line Items]
Valuation allowance	$0

Other_Assets_Details

Other Assets (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Net deferred income tax assets	$35,689	$45,851
Fee receivables	26,211	23,959
Accrued interest receivables	10,560	10,061
Forgivable loans, net	9,685	8,366
Income tax receivables	17,792	0
Prepaid expenses	5,215	6,067
Other	9,412	5,995
Total other assets	$114,564	$100,299

ShortTerm_Financing_Summary_of

Short-Term Financing - Summary of Short Term Financing and Weighted Average Interest Rate on Borrowings (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Short-term Debt [Line Items]
Oustanding Balance	$517,522,000	$377,767,000
Commercial paper (secured)
Short-term Debt [Line Items]
Oustanding Balance	245,994,000	238,013,000
Weighted Average Interest Rate	1.52%	1.48%
Prime broker arrangement
Short-term Debt [Line Items]
Oustanding Balance	220,528,000	127,754,000
Weighted Average Interest Rate	0.93%	0.91%
Bank lines (secured)
Short-term Debt [Line Items]
Oustanding Balance	51,000,000	12,000,000
Weighted Average Interest Rate	1.11%	1.50%
CP Series II A | Commercial paper (secured)
Short-term Debt [Line Items]
Oustanding Balance	$0

ShortTerm_Financing_Additional

Short-Term Financing - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Short-term Debt [Line Items]
Short-term financing	517,522,000	$377,767,000
Commercial paper (secured)
Short-term Debt [Line Items]
Number of commercial paper programs	3
Short-term financing	245,994,000	238,013,000
Commercial paper (secured) | Minimum
Short-term Debt [Line Items]
Debt term	27 days
Commercial paper (secured) | Maximum
Short-term Debt [Line Items]
Debt term	270 days
Commercial paper (secured) | CP Series A | Weighted Average
Short-term Debt [Line Items]
Debt term	85 days
Commercial paper (secured) | CP Series II A
Short-term Debt [Line Items]
Short-term financing	0
Commercial paper (secured) | CP Series III A
Short-term Debt [Line Items]
Excess net capital required	120,000,000
Commercial paper (secured) | CP Series III A | Weighted Average
Short-term Debt [Line Items]
Debt term	12 days
Bank lines (secured)
Short-term Debt [Line Items]
Short-term financing	51,000,000	12,000,000
Bank lines (secured) | Committed Credit Facility
Short-term Debt [Line Items]
Debt term	1 year
Line of credity, maximum borrowing capacity	250,000,000
Minimum net capital required	120,000,000
Short-term financing	21,000,000
Bank lines (secured) | Uncommitted Credit Facility
Short-term Debt [Line Items]
Line of credity, maximum borrowing capacity	185,000,000
Short-term financing	30,000,000
Number of banks	2

Variable_Rate_Senior_Notes_Add

Variable Rate Senior Notes - Additional Information (Details) (Senior Notes, USD $)	3 Months Ended
	Mar. 31, 2015	Nov. 30, 2012	Jun. 02, 2014
		class
Debt Instrument [Line Items]
Face amount		$125,000,000
Number of classes of notes		2
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
Class A Variable Rate Senior Notes Due May 2014
Debt Instrument [Line Items]
Face amount		50,000,000
Class A Variable Rate Senior Notes Due May 2017
Debt Instrument [Line Items]
Face amount			50,000,000
Class A Variable Rate Senior Notes Due May 2017 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
Reference rate	P3M
Class B Variable Rate Senior Notes Due November 2015
Debt Instrument [Line Items]
Face amount		$75,000,000
Class B Variable Rate Senior Notes Due November 2015 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	4.50%
Reference rate	P3M

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Sep. 30, 2014
Equity, Class of Treasury Stock [Line Items]
Aggregate purchase price	$42,566,000	$7,346,000
Stockholders' Equity Attributable to Noncontrolling Interest	156,183,000		149,548,000
Shares of common stock purchased from restricted stock award related to recipients' employment tax obligations	178,928
Repurchase of common stock for employee tax withholding	9,846,000
Reissuance of treasury shares as a result of employee vesting	518,106	445,114
Number of common stock issued for retirement plan obligations	0	103,598
Reissuance of treasury shares for retirement plan obligations	0	4,156,000
Other comprehensive income or loss attributed to noncontrolling interests	0	0
Share Repurchase Program Authorized 2014
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock, authorized amount				100,000,000
Shares repurchased	604,994
Average share price	$54.08
Aggregate purchase price	32,700,000
Repurchase of common stock, amount remaining under this authorization	67,300,000
Municipal bond fund
Equity, Class of Treasury Stock [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	123,500,000		117,000,000
Merchant banking fund
Equity, Class of Treasury Stock [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	24,400,000		24,700,000
Other private equity investments
Equity, Class of Treasury Stock [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	$8,300,000		$7,800,000

Shareholders_Equity_Rollforwar

Shareholders' Equity - Rollforward (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common Shareholders' Equity, Balance at December 31, 2014	$819,912
Noncontrolling interests, Balance at December 31, 2014	149,548
Total Shareholders' Equity, Balance at December 31, 2014	969,460
Common Shareholders' Equity, Net income	16,972	17,748
Noncontrolling Interests, Net income	4,830	5,138
Total Shareholders' Equity, Net income	21,802	22,886
Amortization/issuance of restricted stock	31,884
Issuance of treasury shares for options exercised	1,562
Repurchased of common stock through share repurchase program	-32,720
Repurchase of common stock for employee tax withholding	-9,846
Excess tax benefit from stock-based compensation	3,662
Other comprehensive income	-475
Fund capital contributions, net	-1,805
Common Shareholders' Equity, Balance at March 31, 2015	830,951
Noncontrolling interest, ending balance	156,183
Total Shareholders' Equity, Balance at March 31, 2015	987,134
Parent
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Amortization/issuance of restricted stock	31,884
Issuance of treasury shares for options exercised	1,562
Repurchased of common stock through share repurchase program	-32,720
Repurchase of common stock for employee tax withholding	-9,846
Excess tax benefit from stock-based compensation	3,662
Other comprehensive income	-475
Fund capital contributions, net	0
Noncontrolling Interests
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Amortization/issuance of restricted stock	0
Issuance of treasury shares for options exercised	0
Repurchased of common stock through share repurchase program	0
Repurchase of common stock for employee tax withholding	0
Excess tax benefit from stock-based compensation	0
Fund capital contributions, net	$1,805

Compensation_Plans_Summary_of_

Compensation Plans - Summary of Outstanding Equity Awards (Details)	Mar. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	166,915	217,873
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	1,167,356	1,095,305
Leadership grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	405,826	405,826
Amended And Restated 2003 Annual And Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	1,167,356
Stock options outstanding	166,915
Amended And Restated 2003 Annual And Long-Term Incentive Plan | Annual grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	947,122
Amended And Restated 2003 Annual And Long-Term Incentive Plan | Sign-on grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	220,234
Amended And Restated 2003 Annual And Long-Term Incentive Plan | Leadership grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock outstanding	405,826

Compensation_Plans_RSU_Valuati

Compensation Plans - RSU Valuation Assumptions (Details) (Restricted Stock Units)	3 Months Ended
	Mar. 31, 2015
2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	0.82%
Expected Stock Price Volatility	41.30%
2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	0.40%
Expected Stock Price Volatility	44.00%
2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	0.38%
Expected Stock Price Volatility	47.60%

Compensation_Plans_Unvested_Re

Compensation Plans - Unvested Restricted Stock (Details) (Restricted Stock, USD $)	3 Months Ended
	Mar. 31, 2015
Restricted Stock
Unvested Restricted Stock or Stock Units
Beginning Balance	1,095,305
Granted	552,460
Vested	-477,149
Cancelled	-3,260
Ending Balance	1,167,356
Weighted Average Grant Date Fair Value (in dollars per share)
Beginning Balance	$36.51
Granted	$55.26
Vested	$34.20
Cancelled	$30.61
Ending Balance	$46.34

Compensation_Plans_Unvested_Re1

Compensation Plans - Unvested Restricted Stock Units (Details) (Restricted Stock Units, USD $)	3 Months Ended
	Mar. 31, 2015
Restricted Stock Units
Unvested Restricted Stock or Stock Units
Beginning Balance	405,826
Granted	0
Vested	0
Cancelled	0
Ending Balance	405,826
Weighted Average Grant Date Fair Value (in dollars per share)
Beginning Balance	$17.99
Granted	$0
Vested	$0
Cancelled	$0
Ending Balance	$17.99

Compensation_Plans_Stock_Optio

Compensation Plans - Stock Options (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Options Outstanding
Beginning Balance	217,873
Granted	0
Exercised	-40,957
Cancelled	0
Expired	-10,001
Ending Balance	166,915
Options exercisable at period end	166,915
Weighted Average Exercise Price (in dollars per share)
Beginning Balance	$46.66
Granted	$0
Exercised	$38.14
Cancelled	$0
Expired	$39.62
Ending Balance	$49.17
Options exercisable at period end	$49.17
Weighted Average Remaining Contractual Term (in Years)
Weighted Average Remaining Contractual Term (in Years)	2 years 3 months 10 days	2 years
Options exercisable at period end	2 years 3 months 10 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$1,392,298		$3,066,839
Options exercisable at end of period	$1,392,298

Compensation_Plans_Additional_

Compensation Plans - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	15-May-12	Dec. 31, 2010
	plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans	1
Compensation expense related to employee restricted stock awards	$13,800,000	$5,300,000
Forfeitures recorded as a result of violating the post-termination restrictions	100,000	0
Tax benefit related to compensation costs for stock-based compensation arrangements	5,400,000	2,000,000
Intrinsic value of options exercised	700,000
Tax benefit realized from exercise of options	300,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted, share	552,460
Unrecognized compensation cost related to restricted stock	8,700,000
Weighted average period over which restricted stock expense expected to be recognized	2 years 4 months 20 days
Annual grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years	3 years
Annual grant expense period	1 year
Sign-on grants | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant requisite service period	2 years
Sign-on grants | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant requisite service period	5 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant requisite service period			3 years
Award earning percentage based on peer group	50.00%
Award earning percentage based on shareholder return	50.00%
Restricted stock units, performance period			36 months
Number of years risk free interest rate	3 years
Restricted shares granted, share	0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to restricted stock	0
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of stock options	10 years
Amended And Restated 2003 Annual And Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award grants authorized	7,000,000
Shares available for future issuance	600,000
2010 Employment Inducement Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years				5 years
Restricted shares granted to ARI employees, value				$7,000,000
Restricted shares granted, share				158,801

Compensation_Plans_Compensatio

Compensation Plans Compensation Plans - Deferred Compensation Plans (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Nonqualified Deferred Compensation Plan
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets	15.2
Deferred Compensation Liabilities	15.2
Mutual Fund Restricted Shares
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Award Vesting Period	3 years
New Employees | Mutual Fund Restricted Shares | Minimum
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Requisite Service Period	2 years
New Employees | Mutual Fund Restricted Shares | Maximum
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Requisite Service Period	5 years

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income applicable to Piper Jaffray Companies	$16,972	$17,748
Earnings allocated to participating securities	1,162	1,659
Net income applicable to Piper Jaffray Companies' common shareholders	$15,810	$16,089
Shares for basic and diluted calculations:
Average shares used in basic computation	15,294,000	14,612,000
Average shares used in diluted computation	15,332,000	14,657,000
Earnings per common share
Basic	$1.03	$1.10
Diluted	$1.03	$1.10
Weighted average participating shares outstanding	1,126,906	1,510,839
Stock options
Shares for basic and diluted calculations:
Stock options	38,000	45,000

Segment_Reporting_Reportable_S

Segment Reporting - Reportable Segment Financial Results (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Investment banking	$87,077	$88,474
Institutional sales and trading	36,036	44,034
Management and performance fees	20,522	20,959
Investment income	12,591	6,768
Net revenues	161,871	168,133
Operating expenses	130,579	135,420
Segment pre-tax operating income	31,292	32,713
Segment pre-tax operating margin	19.30%	19.50%
Intangible asset amortization expense	1,773	2,318
Capital Markets
Segment Reporting Information [Line Items]
Investment banking	87,493	88,568
Institutional sales and trading	40,122	49,498
Management and performance fees	1,407	1,737
Investment income	14,705	10,378
Long-term financing expenses	1,560	1,740
Net revenues	142,167	148,441
Operating expenses	116,203	120,930
Segment pre-tax operating income	25,964	27,511
Segment pre-tax operating margin	18.30%	18.50%
Intangible asset amortization expense	263	743
Capital Markets | Equities Financing
Segment Reporting Information [Line Items]
Investment banking	36,489	35,301
Capital Markets | Debt Financing
Segment Reporting Information [Line Items]
Investment banking	21,738	13,539
Capital Markets | Advisory Services
Segment Reporting Information [Line Items]
Investment banking	29,266	39,728
Capital Markets | Equity securities
Segment Reporting Information [Line Items]
Institutional sales and trading	18,905	24,260
Capital Markets | Debt securities
Segment Reporting Information [Line Items]
Institutional sales and trading	21,217	25,238
Asset Mgmt
Segment Reporting Information [Line Items]
Management fees	19,107	19,136
Performance fees	8	86
Management and performance fees	19,115	19,222
Investment income	589	470
Net revenues	19,704	19,692
Operating expenses	14,376	14,490
Segment pre-tax operating income	5,328	5,202
Segment pre-tax operating margin	27.00%	26.40%
Intangible asset amortization expense	$1,510	$1,575

Segment_Reporting_Segment_Repo

Segment Reporting Segment Reporting - Reportable Segment Assets (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$2,917,029	$2,623,917
Capital Markets
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,656,313	2,352,404
Asset Mgmt
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$260,716	$271,513

Net_Capital_Requirements_and_O1

Net Capital Requirements and Other Regulatory Matters - Additional Information (Detail) (USD $)	Mar. 31, 2015
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]
Minimum net capital requirement	$1,000,000
Net capital requirement, percentage of aggregate debit balances arising from customer transactions	2.00%
Net capital requirement, percent of aggregate debit balances under restriction on business expansion or dividend payment	5.00%
Net capital	148,900,000
Minimum net capital required	147,900,000
Senior Notes
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]
Minimum net capital required	120,000,000
Commercial Paper | CP Series III A
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]
Excess net capital required	120,000,000
Committed Credit Facility | Senior Notes
Schedule Of Compliance With Regulatory Capital Requirements For Broker Dealer [Line Items]
Minimum net capital required	$120,000,000