Previously Consolidated Variable Interest Entities (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Previously Consolidated Variable Interest Entities | HeldToMaturity | AAA
Vintage
2003	$ 9,908
2002
2001
2000	2,891
1999
1998	45,956
1997	4,434
Total	63,189
Previously Consolidated Variable Interest Entities | HeldToMaturity | AA
Vintage
2006
2005
2004	24,780
2003
2002
2001
2000
1999
1998	46,315
1997
Total	71,095
Previously Consolidated Variable Interest Entities | HeldToMaturity | A
Vintage
2006
2005
2004	1,935
2003
2002
2001
2000
1999	11,233
1998	37,580
1997	16,159
Total	66,907
Previously Consolidated Variable Interest Entities | HeldToMaturity | BBB
Vintage
2006
2005
2004
2003	3,011
2002
2001
2000
1999	1,414
1998	43,607
1997
Total	48,032
Previously Consolidated Variable Interest Entities | HeldToMaturity | BB
Vintage
2006
2005
2004
2003	1,966
2002	6,712
2001
2000	19,935
1999	17,380
1998	11,900
1997	5,223
Total	63,116
Previously Consolidated Variable Interest Entities | HeldToMaturity | BRatingMember
Vintage
2006
2005
2004
2003
2002
2001	5,426
2000
1999
1998
1997	2,941
Total	8,367
Previously Consolidated Variable Interest Entities | HeldToMaturity | CccAndBelowRatingMember
Vintage
2006	14,884
2005	7,060
2004
2003	1,257
2002	2,283
2001	1,730
2000	3,985
1999
1998	5,000
1997	3,502
Total	40,868
Consolidated Securization Vehicles
Vintage
2006	14,884
2005	7,060
2004	26,715
2003	16,142
2002	8,995
2001	7,156
2000	26,811
1999	30,027
1998	190,358
1997	32,259
Total	$ 361,574