Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) (Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2013	Mar. 31, 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			$ 40,702	$ 42,353	$ 38,847	$ 41,662
Purchases and capital calls	0	0	0	0
Redemptions and distributions	0	1	(98)	(462)
Other comprehensive gain (loss)	2,193	(384)	436	(613)
Balance at end of period	39,671	41,279	39,671	41,279	38,847	41,662
Available-for-sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	0
Available-for-sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	1
Available-for-sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	(1,369)	0	(1,369)	0
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			5,399	5,900	5,193	5,388
Purchases and capital calls	0	0	0	0
Redemptions and distributions	(500)	0	(500)	(500)
Other comprehensive gain (loss)	19	12	(187)	0
Balance at end of period	4,712	5,400	4,712	5,400	5,193	5,388
Available-for-sale Securities [Member] | Other debt securities [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	0
Available-for-sale Securities [Member] | Other debt securities [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	0
Available-for-sale Securities [Member] | Other debt securities [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	0
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			2,161		2,247
Purchases and capital calls	0		0
Redemptions and distributions	0		0
Other comprehensive gain (loss)	1,960		2,046
Balance at end of period	4,207		4,207		2,247
Available-for-sale Securities [Member] | Equity securities and mutual funds [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0		0
Available-for-sale Securities [Member] | Equity securities and mutual funds [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0		0
Available-for-sale Securities [Member] | Equity securities and mutual funds [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0		0
Other Assets [Member] | Private equity funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period			28,169	30,902	28,379	31,492
Purchases and capital calls	567	476	1,207	2,385
Redemptions and distributions	(1,589)	(3,906)	(3,424)	(7,072)
Other comprehensive gain (loss)	0	0	0	0
Balance at end of period	27,799	28,792	27,799	28,792	28,379	31,492
Other Assets [Member] | Private equity funds [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	442	730	1,847	2,577
Other Assets [Member] | Private equity funds [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0	0	0
Other Assets [Member] | Private equity funds [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	$ 0	$ 0	$ 0	$ 0