LOSS AND LOSS ADJUSTMENT RESERVES (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
Jul. 31, 2016	Mar. 31, 2018	Mar. 31, 2017
Claim and claim adjustment expenses incurred related to prior year		$ (2,388)	$ (3,378)
Claim and claim adjustment expenses incurred related to current year		$ 48,459	$ 60,277
Quota Share Treaties [Member] \| Property Insurance Product Line [Member] \| Florida [Member]
Percentage of property quota share reinsurance treaty	30.00%	10.00%

Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65670824&loc=d3e14764-158437

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-18)
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e575016-122915

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration