Segment information (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Information about the Company's segments
Total Revenue	$ 1,087,858	$ 840,784	$ 1,971,082	$ 1,654,824
Net income (loss)	322,358	188,749	528,631	339,704
Business Banking [Member]
Information about the Company's segments
Total Revenue	104,012	102,610	203,789	204,406
Inter-segment revenues	971		1,933
Net income (loss)	26,584	26,552	52,884	51,896
Commercial Banking [Member]
Information about the Company's segments
Total Revenue	228,564	194,575	442,176	386,981
Inter-segment revenues	1,190		2,356
Net income (loss)	95,111	81,612	183,442	158,480
Commercial Real Estate [Member]
Information about the Company's segments
Total Revenue	134,066	109,487	259,372	219,900
Inter-segment revenues	448	39	804	57
Net income (loss)	65,058	43,667	114,068	87,420
Discretionary Portfolio [Member]
Information about the Company's segments
Total Revenue	112,383	5,580	154,866	(6,653)
Inter-segment revenues	(4,419)	(2,500)	(12,206)	(5,247)
Net income (loss)	58,362	(4,073)	74,489	(20,235)
Residential Mortgage Banking [Member]
Information about the Company's segments
Total Revenue	58,305	65,766	116,153	128,883
Inter-segment revenues	8,699	8,876	19,006	17,073
Net income (loss)	5,966	(467)	10,751	128
Retail Banking [Member]
Information about the Company's segments
Total Revenue	311,484	315,638	606,532	623,113
Inter-segment revenues	2,967	2,690	5,954	5,377
Net income (loss)	54,645	67,080	107,371	126,117
All Other [Member]
Information about the Company's segments
Total Revenue	139,044	47,128	188,194	98,194
Inter-segment revenues	(9,856)	(9,105)	(17,847)	(17,260)
Net income (loss)	$ 16,632	$ (25,662)	$ (14,374)	$ (64,102)