Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Available-for-sale Securities [Member] | Municipal and Other Tax Exempt Securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	$ 41,977	$ 43,767	$ 42,353	$ 47,093
Purchases, sales, issuances and settlements, net		0		7,520
Purchases and capital calls	0		0
Redemptions and distributions	(363)	0	(463)	(9,975)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0	0	(576)
Gain on other assets, net	0	0	0	0
Gain on available for sale securities, net	0
Gain on securities, net		0	1	18
Other-than-temporary impairment losses	0	(521)	0	(521)
Other comprehensive gain (loss)	48	412	(229)	99
Balance at end of period	41,662	43,658	41,662	43,658
Available-for-sale Securities [Member] | Other Debt Obligations [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	5,900	5,899	5,900	6,400
Purchases, sales, issuances and settlements, net		0		0
Purchases and capital calls	0		0
Redemptions and distributions	(500)	0	(500)	(500)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0	0	0
Gain on other assets, net	0	0	0	0
Gain on available for sale securities, net	0
Gain on securities, net		0	0	0
Other-than-temporary impairment losses	0	0	0	0
Other comprehensive gain (loss)	(12)	(6)	(12)	(7)
Balance at end of period	5,388	5,893	5,388	5,893
Other Assets [Member] | Private Equity Funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	30,993	25,046	30,902	25,436
Purchases, sales, issuances and settlements, net		746		1,652
Purchases and capital calls	820		1,909
Redemptions and distributions	(2,559)	(783)	(3,166)	(2,185)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0	0	0
Gain on other assets, net	2,238	3,304	1,847	3,410
Gain on available for sale securities, net	0
Gain on securities, net		0	0	0
Other-than-temporary impairment losses	0	0	0	0
Other comprehensive gain (loss)	0	0	0	0
Balance at end of period	$ 31,492	$ 28,313	$ 31,492	$ 28,313