Derivatives (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Derivatives
Total gains/(losses) recorded within Principal transactions	$ (13,800,000)	$ (21,100,000)
Purchase Contracts
Derivatives
Number of Contracts	531	709
Notional	302,725,000	127,816,000
Fair Value	1,018,000	1,696,000
Purchase Contracts | TBA agreements
Derivatives
Number of Contracts	19	1
Notional	202,646,000	589,000
Fair Value	54,000
Purchase Contracts | IRLCs
Derivatives
Number of Contracts	512	708
Notional	100,079,000	127,227,000
Fair Value	964,000	1,696,000
Sale Contracts
Derivatives
Number of Contracts	295	28
Notional	976,076,000	491,900,000
Fair Value	(1,526,000)	(1,971,000)
Sale Contracts | TBA agreements
Derivatives
Number of Contracts	27	17
Notional	708,076,000	371,000,000
Fair Value	(1,511,000)	(1,183,000)
Sale Contracts | Forward agreements
Derivatives
Number of Contracts		11
Notional		120,900,000
Fair Value		(788,000)
Sale Contracts | Eurodollar futures contracts
Derivatives
Number of Contracts	268
Notional	268,000,000
Fair Value	$ (15,000)