Acquisitions	12 Months Ended
Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions	Acquisitions The following acquisitions were accounted for pursuant to FASB Accounting Standards Codification Topic 805, "Business Combinations." Accordingly, the purchase price of each acquisition was allocated to the acquired assets and liabilities assumed based on their estimated fair values as of the respective acquisition dates. The excess of the purchase price over the net assets acquired was allocated between goodwill and intangible assets within the Capital Markets segment. River Branch Holdings LLC and BMO Capital Markets GKST Inc. On September 30, 2015, the Company acquired the assets of River Branch Holdings LLC ("River Branch"), an equity investment banking boutique focused on the financial institutions sector. The purchase was completed pursuant to the Asset Purchase Agreement dated July 11, 2015. On October 9, 2015, the Company completed the purchase of BMO Capital Markets GKST Inc. ("BMO GKST"), a municipal bond sales, trading and origination business of BMO Financial Corp. The purchase was completed pursuant to the Stock Purchase Agreement dated July 19, 2015. The Company recorded $6.1 million of goodwill on the consolidated statements of financial condition. In management's opinion, the goodwill represents the reputation and operating expertise of River Branch and BMO GKST employees. Identifiable intangible assets purchased by the Company consisted of customer relationships with acquisition-date fair values estimated to be $7.5 million. Transaction costs of $0.8 million were incurred for the year ended December 31, 2015, and are included in restructuring and integration costs on the consolidated statements of operations. The results of operations of River Branch and BMO GKST have been included in the Company's consolidated financial statements prospectively from the respective dates of acquisition. The terms of these transactions were not disclosed as the acquisitions did not have a material impact on the Company's consolidated financial statements. Seattle-Northwest Securities Corporation and Edgeview Partners, L.P. On July 12, 2013, the Company completed the purchase of Seattle-Northwest Securities Corporation ("Seattle-Northwest"), a Seattle-based investment bank and broker dealer focused on public finance in the Northwest region of the U.S. The acquisition of Seattle-Northwest supported the Company's strategy to grow its public finance business. On July 16, 2013, the Company completed the purchase of Edgeview Partners, L.P. ("Edgeview"), a middle-market advisory firm specializing in mergers and acquisitions. The acquisition of Edgeview further strengthened the Company's mergers and acquisitions position in the middle market and added resources dedicated to the private equity community. The Company paid $32.7 million in cash for Seattle-Northwest and Edgeview, which represented the fair values as of the respective acquisition dates. The Company also entered into acquisition-related compensation arrangements of $14.3 million which consisted of cash, restricted stock and restricted mutual fund shares ("MFRS Awards") of registered funds managed by the Company's asset management business. Compensation expense related to these arrangements is amortized on a straight-line basis over the original requisite service period of two to five years (a weighted average remaining service period of 2.0 years). The Company recorded $15.0 million of goodwill on the consolidated statements of financial condition, of which $9.1 million is expected to be deductible for income tax purposes. In management's opinion, the goodwill represents the reputation and expertise of Seattle-Northwest and Edgeview employees. Identifiable intangible assets purchased by the Company consisted of customer relationships and non-competition agreements with acquisition-date fair values estimated to be $6.0 million and $0.7 million, respectively. Transaction costs of $1.1 million were incurred for the year ended December 31, 2013, and are included in restructuring and integration costs within continuing operations on the consolidated statements of operations. Definitive Agreement to Acquire Simmons & Company International On November 16, 2015, the Company entered into a Securities Purchase Agreement ("Purchase Agreement") with Simmons & Company International ("Simmons"), an employee-owned investment bank and broker dealer focused on the energy industry. Pursuant to the Purchase Agreement, the Company agreed to purchase 100 percent of the capital stock of Simmons and its subsidiaries for total consideration of approximately $139.0 million, consisting of $91.0 million in cash and $48.0 million of restricted stock. The Company has committed an additional $21.0 million in cash and stock for retention purposes. The transaction is expected to close in the first quarter of 2016.

Acquisitions

The following acquisitions were accounted for pursuant to FASB Accounting Standards Codification Topic 805, "Business Combinations." Accordingly, the purchase price of each acquisition was allocated to the acquired assets and liabilities assumed based on their estimated fair values as of the respective acquisition dates. The excess of the purchase price over the net assets acquired was allocated between goodwill and intangible assets within the Capital Markets segment.

River Branch Holdings LLC and BMO Capital Markets GKST Inc.

On September 30, 2015, the Company acquired the assets of River Branch Holdings LLC ("River Branch"), an equity investment banking boutique focused on the financial institutions sector. The purchase was completed pursuant to the Asset Purchase Agreement dated July 11, 2015.

On October 9, 2015, the Company completed the purchase of BMO Capital Markets GKST Inc. ("BMO GKST"), a municipal bond sales, trading and origination business of BMO Financial Corp. The purchase was completed pursuant to the Stock Purchase Agreement dated July 19, 2015.

The Company recorded $6.1 million of goodwill on the consolidated statements of financial condition. In management's opinion, the goodwill represents the reputation and operating expertise of River Branch and BMO GKST employees.

Identifiable intangible assets purchased by the Company consisted of customer relationships with acquisition-date fair values estimated to be $7.5 million. Transaction costs of $0.8 million were incurred for the year ended December 31, 2015, and are included in restructuring and integration costs on the consolidated statements of operations.

The results of operations of River Branch and BMO GKST have been included in the Company's consolidated financial statements prospectively from the respective dates of acquisition. The terms of these transactions were not disclosed as the acquisitions did not have a material impact on the Company's consolidated financial statements.

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

On July 12, 2013, the Company completed the purchase of Seattle-Northwest Securities Corporation ("Seattle-Northwest"), a Seattle-based investment bank and broker dealer focused on public finance in the Northwest region of the U.S. The acquisition of Seattle-Northwest supported the Company's strategy to grow its public finance business.

On July 16, 2013, the Company completed the purchase of Edgeview Partners, L.P. ("Edgeview"), a middle-market advisory firm specializing in mergers and acquisitions. The acquisition of Edgeview further strengthened the Company's mergers and acquisitions position in the middle market and added resources dedicated to the private equity community.

The Company paid $32.7 million in cash for Seattle-Northwest and Edgeview, which represented the fair values as of the respective acquisition dates. The Company also entered into acquisition-related compensation arrangements of $14.3 million which consisted of cash, restricted stock and restricted mutual fund shares ("MFRS Awards") of registered funds managed by the Company's asset management business. Compensation expense related to these arrangements is amortized on a straight-line basis over the original requisite service period of two to five years (a weighted average remaining service period of 2.0 years).

The Company recorded $15.0 million of goodwill on the consolidated statements of financial condition, of which $9.1 million is expected to be deductible for income tax purposes. In management's opinion, the goodwill represents the reputation and expertise of Seattle-Northwest and Edgeview employees.

Identifiable intangible assets purchased by the Company consisted of customer relationships and non-competition agreements with acquisition-date fair values estimated to be $6.0 million and $0.7 million, respectively. Transaction costs of $1.1 million were incurred for the year ended December 31, 2013, and are included in restructuring and integration costs within continuing operations on the consolidated statements of operations.

Definitive Agreement to Acquire Simmons & Company International

On November 16, 2015, the Company entered into a Securities Purchase Agreement ("Purchase Agreement") with Simmons & Company International ("Simmons"), an employee-owned investment bank and broker dealer focused on the energy industry. Pursuant to the Purchase Agreement, the Company agreed to purchase 100 percent of the capital stock of Simmons and its subsidiaries for total consideration of approximately $139.0 million, consisting of $91.0 million in cash and $48.0 million of restricted stock. The Company has committed an additional $21.0 million in cash and stock for retention purposes. The transaction is expected to close in the first quarter of 2016.