Investments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments, Amortized Cost	$ 409,613	$ 411,043
Investments, Gross Unrealized Gains	20,876	20,059
Investments, Gross Unrealized Losses	(4,507)	(6,474)
Investments, Fair Value	425,982	424,628
Equity Securities [Member]
Investments, Amortized Cost	29,118	30,465
Investments, Gross Unrealized Gains	12,616	14,017
Investments, Gross Unrealized Losses	(40)	(323)
Investments, Fair Value	41,694	44,159
Debt Securities [Member]
Investments, Amortized Cost	380,495	380,578
Investments, Gross Unrealized Gains	8,260	6,042
Investments, Gross Unrealized Losses	(4,467)	(6,151)
Investments, Fair Value	384,288	380,469
US Treasury Securities and Obligation [Member] | Debt Securities [Member]
Investments, Amortized Cost	16,082	11,152
Investments, Gross Unrealized Gains	19	24
Investments, Gross Unrealized Losses	0	0
Investments, Fair Value	16,101	11,176
Corporate Bond Securities [Member] | Debt Securities [Member]
Investments, Amortized Cost	88,459	93,272
Investments, Gross Unrealized Gains	2,829	2,305
Investments, Gross Unrealized Losses	(964)	(1,655)
Investments, Fair Value	90,324	93,922
Collateralized Corporate Bank Loans [Member] | Debt Securities [Member]
Investments, Amortized Cost	109,010	94,638
Investments, Gross Unrealized Gains	976	175
Investments, Gross Unrealized Losses	(653)	(1,920)
Investments, Fair Value	109,333	92,893
Municipal Bonds [Member] | Debt Securities [Member]
Investments, Amortized Cost	163,796	177,432
Investments, Gross Unrealized Gains	4,330	3,458
Investments, Gross Unrealized Losses	(2,841)	(2,549)
Investments, Fair Value	165,285	178,341
Collateralized Mortgage Backed Securities [Member] | Debt Securities [Member]
Investments, Amortized Cost	3,148	4,084
Investments, Gross Unrealized Gains	106	80
Investments, Gross Unrealized Losses	(9)	(27)
Investments, Fair Value	3,245	4,137
Equity Securities Financial Services [Member] | Equity Securities [Member]
Investments, Amortized Cost	11,004	11,618
Investments, Gross Unrealized Gains	3,648	4,463
Investments, Gross Unrealized Losses	(1)	(260)
Investments, Fair Value	14,651	15,821
Equity Securities, Other [Member] | Equity Securities [Member]
Investments, Amortized Cost	18,114	18,847
Investments, Gross Unrealized Gains	8,968	9,554
Investments, Gross Unrealized Losses	(39)	(63)
Investments, Fair Value	$ 27,043	$ 28,338