Derivatives (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012 Purchase Contracts item	Dec. 31, 2012 Purchase Contracts TBA agreements item	Dec. 31, 2012 Purchase Contracts IRLCs item	Mar. 31, 2013 Sale Contracts item	Dec. 31, 2012 Sale Contracts item	Mar. 31, 2013 Sale Contracts TBA agreements item	Dec. 31, 2012 Sale Contracts TBA agreements item	Dec. 31, 2012 Sale Contracts Eurodollar futures contracts item
Derivatives
Number of Contracts			531	19	512	6,000	295	6,000	27	268
Notional			$ 302,725,000	$ 202,646,000	$ 100,079,000	$ 349,367,000	$ 976,076,000	$ 349,367,000	$ 708,076,000	$ 268,000,000
Fair Value			1,018,000	54,000	964,000	1,640,000	(1,526,000)	1,640,000	(1,511,000)	(15,000)
Total gains/(losses) related to continuing operations (excluding ClearPoint), recorded within Principal transactions	$ 1,600,000	$ (1,900,000)