STOCK-BASED COMPENSATION PLANS: (Details 4) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended											0 Months Ended			12 Months Ended		0 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 SARs	Dec. 31, 2011 SARs	Dec. 31, 2010 SARs	Dec. 31, 2012 Subsidiary Stock Awards	Dec. 31, 2011 Subsidiary Stock Awards	Dec. 31, 2012 Stock Grants to Non-Employee Directors	Dec. 31, 2011 Stock Grants to Non-Employee Directors	Dec. 31, 2010 Stock Grants to Non-Employee Directors	Mar. 09, 2012 LTIP SARs David Smith, President and Chief Executive Officer	Mar. 22, 2011 LTIP SARs David Smith, President and Chief Executive Officer	Mar. 12, 2010 LTIP SARs David Smith, President and Chief Executive Officer	Dec. 31, 2012 LTIP SARs David Smith, President and Chief Executive Officer	Dec. 31, 2011 LTIP SARs David Smith, President and Chief Executive Officer	Jun. 14, 2012 LTIP Stock Grants to Non-Employee Directors Class A Common Stock	Jun. 03, 2011 LTIP Stock Grants to Non-Employee Directors Class A Common Stock	Jun. 03, 2010 LTIP Stock Grants to Non-Employee Directors Class A Common Stock	Dec. 31, 2012 LTIP Stock Grants to Non-Employee Directors Class A Common Stock	Dec. 31, 2011 LTIP Stock Grants to Non-Employee Directors Class A Common Stock	Dec. 31, 2010 LTIP Stock Grants to Non-Employee Directors Class A Common Stock
SARs
Base value of rights granted (in dollars per share)												$ 11.68	$ 12.07	$ 5.75
Grant date fair value of rights granted												$ 2.0	$ 2.2	$ 1.6
Term of rights															10 years
Assumptions used in valuation of SARs
Risk-free interest rate (as a percent)				0.90%	3.60%	3.90%
Expected life				5 years	10 years	10 years
Expected volatility (as a percent)				73.00%	68.00%	110.00%
Annual dividend yield (as a percent)				5.20%	2.30%
SARs
Compensation expense	$ 1.2	$ 1.0	$ 0.8	$ 2.0	$ 2.2	$ 1.6	$ 0.7	$ 2.9	$ 0.2	$ 0.2	$ 0.2
Number of shares received by non-employee director																				5,000	5,000	5,000
Granted (in shares)																	25,000	25,000	25,000
Fair value (in dollars per share)																	$ 8.12	$ 9.39	$ 6.61
SARs
Outstanding at the beginning of the year (in shares)				500,000											237,947
Granted (in shares)				400,000								400,000	300,000	300,000
Outstanding at the end of the year (in shares)				900,000	500,000											237,947
Exercised (in shares)																650,000
Weighted-Average Price
Outstanding at the beginning of the year (in dollars per share)				$ 13.55
Granted (in dollars per share)				$ 11.68
Outstanding at the end of the year (in dollars per share)				$ 12.72	$ 13.55