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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
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	$ 39,007	$ 41,977	$ 40,702	$ 42,353
Purchases and capital calls	0	0	0	0
Redemptions and distributions	0	(363)	(98)	(463)
Gain (loss) recognized in earnings [Abstract]
Gain on other assets, net	0	0	0	0
Gain on available for sale securities net	0	0	0	1
Other-than-temporary impairment losses	0	0	0	0
Other comprehensive gain (loss)	(160)	48	(1,757)	(229)
Balance at end of period	38,847	41,662	38,847	41,662
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	5,193	5,900	5,399	5,900
Purchases and capital calls	0	0	0	0
Redemptions and distributions	0	(500)	0	(500)
Gain (loss) recognized in earnings [Abstract]
Gain on other assets, net	0	0	0	0
Gain on available for sale securities net	0	0	0	0
Other-than-temporary impairment losses	0	0	0	0
Other comprehensive gain (loss)	0	(12)	(206)	(12)
Balance at end of period	5,193	5,388	5,193	5,388
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	2,472		2,161
Purchases and capital calls	0		0
Redemptions and distributions	0		0
Gain (loss) recognized in earnings [Abstract]
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)	(225)		86
Balance at end of period	2,247		2,247
Other Assets [Member] | Private Equity Funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	29,216	30,993	28,169	30,902
Purchases and capital calls	148	820	640	1,909
Redemptions and distributions	(1,005)	(2,559)	(1,835)	(3,166)
Gain (loss) recognized in earnings [Abstract]
Gain on other assets, net	20	2,238	1,405	1,847
Gain on available for sale securities net	0	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	$ 28,379	$ 31,492	$ 28,379	$ 31,492