MORTGAGE LOANS (Details 2) (Commercial mortgage loans, USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 item	Dec. 31, 2012
Commercial mortgage loans
Mortgage loans
Mortgage loans having participation feature	$ 705,700,000	$ 705,700,000	$ 817,300,000
Income recognized on participating mortgage loans	5,800,000	9,200,000
Maximum nonperforming mortgage loans, foreclosed properties and restructured loans to invested assets (as a percent)	0.05%	0.05%
Maximum nonperforming mortgage loans, foreclosed properties and restructured loans pursuant to pooling and servicing agreement	17,600,000	17,600,000
Number of loan categories		2
Nonperforming loans not subject to a pooling and servicing agreement	15,400,000	15,400,000
Loans subject to a pooling and servicing agreement which are either nonperforming or restructured	2,200,000	2,200,000
Number of nonperforming loans subject to a pooling and servicing agreement which have been restructured		0
Change in the allowance for credit losses
Beginning balance		2,875,000	6,475,000
Charge offs		(2,292,000)	(9,840,000)
Recoveries		(374,000)	(628,000)
Provision		6,826,000	6,868,000
Ending balance	$ 7,035,000	$ 7,035,000	$ 2,875,000