DEBT AND OTHER OBLIGATIONS (Details) (USD $)	9 Months Ended			9 Months Ended				9 Months Ended			9 Months Ended		0 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended			0 Months Ended																		0 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Golden Gate II Captive Insurance Company	Sep. 30, 2013 Golden Gate V Vermont Captive Insurance Company	Sep. 30, 2013 Red Mountain	Oct. 10, 2012 Red Mountain	Sep. 30, 2013 Golden Gate III Vermont Captive Insurance Company (Golden Gate III) item	Aug. 07, 2013 Golden Gate III Vermont Captive Insurance Company (Golden Gate III)	Apr. 23, 2010 Golden Gate III Vermont Captive Insurance Company (Golden Gate III)	Sep. 30, 2013 Golden Gate IV Vermont Captive Insurance Company (Golden Gate IV)	Dec. 10, 2010 Golden Gate IV Vermont Captive Insurance Company (Golden Gate IV)	Oct. 10, 2012 Golden Gate V and Red Mountain	Sep. 30, 2013 Repurchase Program Borrowings	Dec. 31, 2012 Repurchase Program Borrowings	Sep. 30, 2013 Repurchase Program Borrowings Maximum	Sep. 30, 2013 Revolving Line of Credit	Dec. 31, 2012 Revolving Line of Credit	Jun. 03, 2013 4.30% Senior Notes (2003), due 2013	Dec. 31, 2012 4.30% Senior Notes (2003), due 2013	Sep. 30, 2013 4.875% Senior Notes (2004), due 2014	Dec. 31, 2012 4.875% Senior Notes (2004), due 2014	Sep. 30, 2013 6.40% Senior Notes (2007), due 2018	Dec. 31, 2012 6.40% Senior Notes (2007), due 2018	Sep. 30, 2013 7.375% Senior Notes (2009), due 2019	Dec. 31, 2012 7.375% Senior Notes (2009), due 2019	Sep. 30, 2013 8.00% Senior Notes (2009), due 2024, callable 2014	Dec. 31, 2012 8.00% Senior Notes (2009), due 2024, callable 2014	Sep. 30, 2013 8.45% Senior Notes (2009), due 2039	Dec. 31, 2012 8.45% Senior Notes (2009), due 2039	Sep. 30, 2013 6.125% Subordinated Debentures (2004), due 2034, callable 2009	Dec. 31, 2012 6.125% Subordinated Debentures (2004), due 2034, callable 2009	Sep. 30, 2013 6.25% Subordinated Debentures (2012) due 2042, callable 2017	Dec. 31, 2012 6.25% Subordinated Debentures (2012) due 2042, callable 2017	Sep. 30, 2013 6.00% Subordinated Debentures (2012) due 2042, callable 2017	Dec. 31, 2012 6.00% Subordinated Debentures (2012) due 2042, callable 2017	Jun. 03, 2013 Credit Facility	Sep. 30, 2013 Credit Facility	Sep. 30, 2013 Credit Facility Federal Funds Rate	Sep. 30, 2013 Credit Facility Prime Rate	Sep. 30, 2013 Credit Facility LIBOR One-Month Rate
Debt and other obligations
Stated interest rate (as a percent)																				4.30%	4.875%	4.875%	6.40%	6.40%	7.375%	7.375%	8.00%	8.00%	8.45%	8.45%	6.125%	6.125%	6.25%	6.25%	6.00%	6.00%
Total debt	$ 1,450,000,000		$ 1,400,000,000														$ 350,000,000	$ 50,000,000		$ 250,000,000	$ 150,000,000	$ 150,000,000	$ 150,000,000	$ 150,000,000	$ 400,000,000	$ 400,000,000	$ 100,000,000	$ 100,000,000	$ 300,000,000	$ 300,000,000
Total subordinated debt securities	540,593,000		540,593,000																												103,093,000	103,093,000	287,500,000	287,500,000	150,000,000	150,000,000
Line of credit, current borrowing capacity																																						750,000,000
Line of credit, maximum borrowing capacity to be granted upon entity's request																																						1,000,000,000
Base of floating rate interest rate payments																																						LIBOR	Federal Funds rate	Prime rate	one-month LIBOR
Interest rate added to the base rate (as a percent)																																						1.20%	0.50%		1.00%
Line of credit, amount outstanding																																						350,000,000
Repayment of debt																			250,000,000
Borrowing of additional line of credit																																					250,000,000
Outstanding non-recourse funding obligations of Golden Gate II Captive Insurance Company	575,000,000
Term of transaction													20 years
Maximum financing capacity under transaction							945,000,000						945,000,000
Principal amount of note issued						350,000,000	275,000,000
Non-recourse funding obligations	619,900,000		586,000,000	269,900,000	350,000,000
Non-recourse funding obligations held by affiliates	305,100,000
Expected payments under support agreement obligation				0	0			0			0
Future scheduled capital contributions					144,300,000			149,800,000
Year-to-date weighted-average interest rate of non-recourse funding obligations (as a percent)				0.99%	6.25%
Outstanding nonrecourse funding obligations repurchased at discount	16,100,000	110,800,000
Gain from repurchase of outstanding nonrecourse funding obligations	3,400,000	35,500,000
Maximum borrowing capacity under letter of credit									710,000,000	505,000,000	690,000,000	270,000,000
Maximum amount up to which LOC will be periodically increased								720,000,000		610,000,000	790,000,000
Outstanding letters of credit (LOC)								710,000,000
Letter of credit term								13 years 6 months			12 years
Number of installments in which future scheduled capital contributions payable								3
Fair value of securities pledged under the repurchase program														109,600,000
Repurchase program borrowings	100,000,000		150,000,000											100,000,000
Average borrowing rate (as a percent)														0.11%
Maximum balance outstanding														645,100,000	425,000,000
Average daily balance														417,500,000	266,300,000
Average borrowing rate (as a percent)														0.11%	0.14%
Outstanding balance															$ 150,000,000
Term of debt																90 days