Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 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	$ 42,353	$ 47,093
Transfers to Level 3 from Level 2	0
Purchases and capital calls	0	7,520
Redemptions and distributions	(988)	(10,625)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		(576)
Gain on other assets, net	0	0
Gain on available for sale securities, net	1	21
Other-than-temporary impairment losses	(642)	(1,558)
Other comprehensive gain (loss)	(22)	478
Balance at end of period	40,702	42,353
Available-for-sale Securities [Member] | Other Debt Securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	5,900	6,400
Transfers to Level 3 from Level 2	0
Purchases and capital calls	0	0
Redemptions and distributions	(500)	(500)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0
Gain on other assets, net	0	0
Gain on available for sale securities, net	0	0
Other-than-temporary impairment losses	0	0
Other comprehensive gain (loss)	(1)	0
Balance at end of period	5,399	5,900
Available-for-sale Securities [Member] | Equity securities and mutual funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	0	0
Transfers to Level 3 from Level 2	2,161
Purchases and capital calls	0	0
Redemptions and distributions	0	0
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0
Gain on other assets, net	0	0
Gain on available for sale securities, net	0	0
Other-than-temporary impairment losses	0	0
Other comprehensive gain (loss)	0	0
Balance at end of period	2,161	0
Other Assets [Member] | Private Equity Funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	30,902	25,436
Transfers to Level 3 from Level 2	0
Purchases and capital calls	3,446	4,052
Redemptions and distributions	(9,819)	(3,903)
Gain (loss) recognized in earnings [Abstract]
Brokerage and trading revenue		0
Gain on other assets, net	3,640	5,317
Gain on available for sale securities, net	0	0
Other-than-temporary impairment losses	0	0
Other comprehensive gain (loss)	0	0
Balance at end of period	$ 28,169	$ 30,902