Acquisitions Acquisitions (Notes)	3 Months Ended
Dec. 31, 2018
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Note 17 - Acquisitions Carl Kliem S.A. On June 12, 2018, the Company executed a sale and purchase agreement to acquire the entire issued and outstanding share capital of Carl Kliem S.A. Carl Kliem S.A. is an independent interdealer broker based in Luxembourg, which provides foreign exchange, interest rate and fixed income products to institutional clients across the European Union. Carl Kliem S.A. employs approximately 40 people and has over 400 active institutional clients. This acquisition provides the Company with access to additional European institutional clients that can benefit from the Company’s full suite of financial services and a European Union-based entity in anticipation of the U.K.’s planned exit from the European Union. The closing of the agreement was conditional upon approval of the Luxembourg financial sector supervisory authority, the Commission de Surveillance du Secteur Financier (“CSSF”). In November 2018, the Company received regulatory approval from the CSSF to complete the acquisition and the acquisition closed effective November 30, 2018. The purchase price was $2.4 million of cash consideration and was equal to the net tangible book value on the closing date less restructuring costs. The initial purchase price allocation resulted in cash and cash equivalents of $1.7 million, receivables from clients of $1.1 million, property and equipment of $0.1 million, income tax receivables of $0.1 million, accounts payable and other accrued liabilities of $0.6 million, and payable to broker-dealers, clearing organizations, and counterparties of $0.2 million. The fair value of the consideration transferred exceeded the fair value of identifiable assets acquired and liabilities assumed as of the acquisition date. The excess of the purchase consideration over the fair value of identifiable assets acquired and liabilities assumed of $0.2 million was recorded as goodwill. The business activities of Carl Kleim S.A. have been included within the Company’s Securities and Clearing and Execution Services reportable segments. The Company’s condensed consolidated income statement for the three months ended December 31, 2018 includes a net loss of $0.2 million for the post-acquisition results of the acquired business.

Note 17 - Acquisitions

Carl Kliem S.A.

On June 12, 2018, the Company executed a sale and purchase agreement to acquire the entire issued and outstanding share capital of Carl Kliem S.A. Carl Kliem S.A. is an independent interdealer broker based in Luxembourg, which provides foreign exchange, interest rate and fixed income products to institutional clients across the European Union. Carl Kliem S.A. employs approximately 40 people and has over 400 active institutional clients. This acquisition provides the Company with access to additional European institutional clients that can benefit from the Company’s full suite of financial services and a European Union-based entity in anticipation of the U.K.’s planned exit from the European Union. The closing of the agreement was conditional upon approval of the Luxembourg financial sector supervisory authority, the Commission de Surveillance du Secteur Financier (“CSSF”). In November 2018, the Company received regulatory approval from the CSSF to complete the acquisition and the acquisition closed effective November 30, 2018. The purchase price was $2.4 million of cash consideration and was equal to the net tangible book value on the closing date less restructuring costs.

The initial purchase price allocation resulted in cash and cash equivalents of $1.7 million, receivables from clients of $1.1 million, property and equipment of $0.1 million, income tax receivables of $0.1 million, accounts payable and other accrued liabilities of $0.6 million, and payable to broker-dealers, clearing organizations, and counterparties of $0.2 million. The fair value of the consideration transferred exceeded the fair value of identifiable assets acquired and liabilities assumed as of the acquisition date. The excess of the purchase consideration over the fair value of identifiable assets acquired and liabilities assumed of $0.2 million was recorded as goodwill. The business activities of Carl Kleim S.A. have been included within the Company’s Securities and Clearing and Execution Services reportable segments. The Company’s condensed consolidated income statement for the three months ended December 31, 2018 includes a net loss of $0.2 million for the post-acquisition results of the acquired business.