Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	$ 6,094,640	$ 6,281,781
Equity securities - available for sale, at fair value	347,840	284,639
Short-term investments*	216,793	363,053
Other Investments	18	20,925
Restricted cash and securities	1,848	2,043
Premium, claims and other receivables	62,118	68,207
Other assets	589	349
Total assets measured at fair value	6,723,846	7,020,997
Notes payable	688,240	636,363
Accounts payable and accrued liabilities - earnout liability	8,981	9,052
Accounts payable and accrued liabilities - forward contract	2,283	3,194
Total liabilities measured at fair value	699,504	648,609
Fair Value, Inputs, Level 1 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	103,294	174,520
Equity securities - available for sale, at fair value	347,840	284,639
Short-term investments*	115,965	251,988
Other Investments Held At Fair Value	18	20,925
Total assets measured at fair value	567,117	732,072
Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	5,981,900	6,107,097
Short-term investments*	100,828	111,065
Restricted cash and securities	1,848	2,043
Premium, claims and other receivables	62,118	68,207
Total assets measured at fair value	6,146,694	6,288,412
Notes payable	688,240	636,363
Accounts payable and accrued liabilities - earnout liability	1,848	2,043
Accounts payable and accrued liabilities - forward contract	2,283	3,194
Total liabilities measured at fair value	692,371	641,600
Fair Value, Inputs, Level 3 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	9,446	164
Other assets	589	349
Total assets measured at fair value	10,035	513
Accounts payable and accrued liabilities - earnout liability	7,133	7,009
Total liabilities measured at fair value	7,133	7,009
US Government and Government Agency Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	123,664	199,607
US Government and Government Agency Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	103,294	174,520
US Government and Government Agency Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	20,370	25,087
Fixed Maturity Securities of States, Municipalities and Political Subdivisions Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	1,029,817	1,065,811
Fixed Maturity Securities of States, Municipalities and Political Subdivisions Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	1,029,817	1,065,811
Special Purpose Revenue Bonds Of States Municipalities And Political Subdivisions [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	2,271,620	2,200,331
Special Purpose Revenue Bonds Of States Municipalities And Political Subdivisions [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	2,262,343	2,200,331
Special Purpose Revenue Bonds Of States Municipalities And Political Subdivisions [Member] \| Fair Value, Inputs, Level 3 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	9,277
Corporate Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	1,236,645	1,315,170
Corporate Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	1,236,476	1,315,006
Corporate Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	169	164
Residential Mortgage Backed Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	605,495	664,887
Residential Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	605,495	664,887
Commercial Mortgage Backed Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	536,199	524,289
Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	536,199	524,289
Asset-backed Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	54,291	33,275
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	54,291	33,275
Foreign Government Securities [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	236,909	278,411
Foreign Government Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities-available for sale
Fixed maturity securities - available for sale	$ 236,909	$ 278,411

No authoritative reference available.

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