Fair Value Measurements (Assets and Liabilities FV) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Available for sale
Fixed maturity securities - available for sale	$ 6,296,256	$ 6,610,368
Equity securities - available for sale, at fair value	390,077	296,352
Short-term investments*	283,420	258,186
Other Investments Carried at Fair Value, Not at Net Asset Value	17
Restricted cash and securities	3,780	2,729
Premium, claims and other receivables	53,749	56,493
Other assets	1,632	1,324
Total assets measured at fair value	7,028,931	7,225,452
Notes payable	951,601	875,094
Accounts payable and accrued liabilities - earnout liabilities	11,310	11,473
Total liabilities measured at fair value	962,911	886,567
Fair Value, Inputs, Level 1 [Member]
Available for sale
Fixed maturity securities - available for sale	68,889	63,663
Equity securities - available for sale, at fair value	390,077	296,352
Short-term investments*	154,674	159,297
Other Investments Carried at Fair Value, Not at Net Asset Value	17
Other assets	0	18
Total assets measured at fair value	613,657	519,330
Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	6,227,220	6,546,557
Short-term investments*	128,746	98,889
Restricted cash and securities	3,780	2,729
Premium, claims and other receivables	53,749	56,493
Total assets measured at fair value	6,413,495	6,704,668
Notes payable	951,601	875,094
Accounts payable and accrued liabilities - earnout liabilities	3,780	2,729
Total liabilities measured at fair value	955,381	877,823
Fair Value, Inputs, Level 3 [Member]
Available for sale
Fixed maturity securities - available for sale	147	148
Other assets	1,632	1,306
Total assets measured at fair value	1,779	1,454
Accounts payable and accrued liabilities - earnout liabilities	7,530	8,744
Total liabilities measured at fair value	7,530	8,744
US Government and Government Agency Securities [Member]
Available for sale
Fixed maturity securities - available for sale	74,138	70,969
US Government and Government Agency Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available for sale
Fixed maturity securities - available for sale	68,889	63,663
US Government and Government Agency Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	5,249	7,306
Fixed Maturity Securities of States, Municipalities and Political Subdivisions Securities [Member]
Available for sale
Fixed maturity securities - available for sale	815,755	954,708
Fixed Maturity Securities of States, Municipalities and Political Subdivisions Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	815,755	954,708
Special Purpose Revenue Bonds Of States Municipalities And Political Subdivisions [Member]
Available for sale
Fixed maturity securities - available for sale	2,338,946	2,389,012
Special Purpose Revenue Bonds Of States Municipalities And Political Subdivisions [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	2,338,946	2,389,012
Corporate Securities [Member]
Available for sale
Fixed maturity securities - available for sale	782,316	798,569
Corporate Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	782,169	798,421
Corporate Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Available for sale
Fixed maturity securities - available for sale	147	148
Residential Mortgage Backed Securities [Member]
Available for sale
Fixed maturity securities - available for sale	792,037	821,694
Residential Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	792,037	821,694
Commercial Mortgage Backed Securities [Member]
Available for sale
Fixed maturity securities - available for sale	532,689	611,631
Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	532,689	611,631
Asset-backed Securities [Member]
Available for sale
Fixed maturity securities - available for sale	372,791	366,827
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	372,791	366,827
Foreign Government Securities [Member]
Available for sale
Fixed maturity securities - available for sale	145,251	118,692
Foreign Government Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	145,251	118,692
Foreign Corporate Securities [Member]
Available for sale
Fixed maturity securities - available for sale	442,333	478,266
Foreign Corporate Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Available for sale
Fixed maturity securities - available for sale	$ 442,333	$ 478,266

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