Investments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments, Amortized Cost	$ 429,302	$ 411,043
Investments, Gross Unrealized Gains	20,887	20,059
Investments, Gross Unrealized Losses	(4,829)	(6,474)
Investments, Fair Value	445,360	424,628
Equity Securities [Member]
Investments, Amortized Cost	31,502	30,465
Investments, Gross Unrealized Gains	12,938	14,017
Investments, Gross Unrealized Losses	(515)	(323)
Investments, Fair Value	43,925	44,159
Debt Securities [Member]
Investments, Amortized Cost	397,800	380,578
Investments, Gross Unrealized Gains	7,949	6,042
Investments, Gross Unrealized Losses	(4,314)	(6,151)
Investments, Fair Value	401,435	380,469
US Treasury Securities and Obligation [Member] | Debt Securities [Member]
Investments, Amortized Cost	40,050	11,152
Investments, Gross Unrealized Gains	14	24
Investments, Gross Unrealized Losses	(3)	0
Investments, Fair Value	40,061	11,176
Corporate Bond Securities [Member] | Debt Securities [Member]
Investments, Amortized Cost	79,516	93,272
Investments, Gross Unrealized Gains	2,794	2,305
Investments, Gross Unrealized Losses	(763)	(1,655)
Investments, Fair Value	81,547	93,922
Collateralized Corporate Bank Loans [Member] | Debt Securities [Member]
Investments, Amortized Cost	106,093	94,638
Investments, Gross Unrealized Gains	1,021	175
Investments, Gross Unrealized Losses	(743)	(1,920)
Investments, Fair Value	106,371	92,893
Municipal Bonds [Member] | Debt Securities [Member]
Investments, Amortized Cost	162,479	177,432
Investments, Gross Unrealized Gains	4,023	3,458
Investments, Gross Unrealized Losses	(2,770)	(2,549)
Investments, Fair Value	163,732	178,341
Collateralized Mortgage Backed Securities [Member] | Debt Securities [Member]
Investments, Amortized Cost	9,662	4,084
Investments, Gross Unrealized Gains	97	80
Investments, Gross Unrealized Losses	(35)	(27)
Investments, Fair Value	9,724	4,137
Equity Securities Financial Services [Member] | Equity Securities [Member]
Investments, Amortized Cost	11,008	11,618
Investments, Gross Unrealized Gains	3,880	4,463
Investments, Gross Unrealized Losses	(1)	(260)
Investments, Fair Value	14,887	15,821
Equity Securities, Other [Member] | Equity Securities [Member]
Investments, Amortized Cost	20,494	18,847
Investments, Gross Unrealized Gains	9,058	9,554
Investments, Gross Unrealized Losses	(514)	(63)
Investments, Fair Value	$ 29,038	$ 28,338