SCHEDULE I-SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) - 10K (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	$ 1,700,295
Fair Value	1,964,285
Amount at which shown in the balance sheet	1,964,285
Debt securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	1,448,204
Fair Value	1,495,087
Amount at which shown in the balance sheet	1,495,087
Debt securities \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	1,448,204
Fair Value	1,495,087
Amount at which shown in the balance sheet	1,495,087
U.S. government \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	33,668
Fair Value	33,788
Amount at which shown in the balance sheet	33,788
U.S. Agency \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	6,385
Fair Value	6,747
Amount at which shown in the balance sheet	6,747
Non-U.S. govt. & agency \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	9,862
Fair Value	10,665
Amount at which shown in the balance sheet	10,665
Mtge/ABS/CMBS \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	390,337
Fair Value	399,772
Amount at which shown in the balance sheet	399,772
Corporate Debt \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	543,183
Fair Value	562,690
Amount at which shown in the balance sheet	562,690
Municipal \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	464,769
Fair Value	481,425
Amount at which shown in the balance sheet	481,425
Equity securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	193,535
Fair Value	410,642
Amount at which shown in the balance sheet	410,642
Ind Misc & all other
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	145,282
Fair Value	320,786
Amount at which shown in the balance sheet	320,786
ETFs (Ind/misc)
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	48,253
Fair Value	89,856
Amount at which shown in the balance sheet	89,856
Cash and Short-term Investments
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	46,959
Fair Value	46,959
Amount at which shown in the balance sheet	46,959
Other Invested Assets
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	11,597
Fair Value	11,597
Amount at which shown in the balance sheet	$ 11,597

This element represents the carrying (reported) amount of the entity's investments as of the balance sheet date. This amount may represent the individual investment's or group of similar investments' original cost, fair value, or such other amount at which the investment is shown in the entity's balance sheet.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 15

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 7

-Subparagraph (SX 210.12-15)

-URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611379-123010

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