INVESTMENT OPERATIONS - Summary of Change in Unrealized Gains (Losses), Net of Income Tax, on Fixed Maturity and Equity Securities, Classified as Available-for-Sale (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Fixed maturities
Investment Holdings [Line Items]
Change in unrealized gains (losses), net of income tax	$ 224,115	$ 632,685
Equity securities
Investment Holdings [Line Items]
Change in unrealized gains (losses), net of income tax	$ 14,569	$ (70)

The change in unrealized holding gain (loss), net of tax, on available-for-sale securities included in a separate component of shareholders' equity during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27357-111563

Name:	us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLossNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration