MORTGAGE LOANS (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014 item	Jun. 30, 2013	Jun. 30, 2014 item	Jun. 30, 2013	Dec. 31, 2013
Mortgage loans
Mortgage loan holdings	$ 5,294,729,000		$ 5,294,729,000		$ 5,493,492,000
Amount that would become due for the remainder of 2014, if loans are called at their next call dates	43,700,000		43,700,000
Amount that would become due in 2015 through 2019, if loans are called at their next call dates	1,100,000,000		1,100,000,000
Amount that would become due in 2020 through 2024, if loans are called at their next call dates	501,400,000		501,400,000
Amount that would become due after 2024, if loans are called at their next call dates	130,500,000		130,500,000
Commercial mortgage loans
Mortgage loans
Mortgage loan holdings	5,300,000,000		5,300,000,000
Mortgage loans having participation feature	613,800,000		613,800,000		666,600,000
Income recognized on participating mortgage loans	2,800,000	5,800,000	5,800,000	9,200,000
Nonperforming mortgage loans, foreclosed properties and restructured loans pursuant to pooling and servicing agreement	5,900,000		5,900,000
Nonperforming mortgage loans, foreclosed properties and restructured loans to invested assets (as a percent)	0.01%		0.01%
Mortgage loans accounted for as troubled debt restructurings	15,100,000		15,100,000
Principle amount accounted for as troubled debt restructurings	16,000,000		16,000,000
Reduction in the entity's investment in mortgage loans, net of existing allowances for mortgage loan losses	900,000		900,000
Number of troubled debt restructuring loans remaining on the balance sheet	0		0
Number of loan categories			2
Nonperforming or restructured loans not subject to a pooling and servicing agreement	3,700,000		3,700,000
Number of nonperforming loans not subject to a pooling and servicing agreement which have been restructured			0
Loans subject to a pooling and servicing agreement which are nonperforming	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			3,130,000	2,875,000	2,875,000
Charge offs					(6,838,000)
Recoveries			(1,075,000)		(1,016,000)
Provision			2,225,000		8,109,000
Ending balance	$ 4,280,000		$ 4,280,000		$ 3,130,000
Commercial mortgage loans | Minimum
Mortgage loans
Period for exercise of call options or interest rate reset options			3 years
Commercial mortgage loans | Maximum
Mortgage loans
Period for exercise of call options or interest rate reset options			10 years
Loan-to-value ratio with participating interest (as a percent)	85.00%		85.00%