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Compensation Programs (Narrative) (Details) (USD $)	9 Months Ended	12 Months Ended		9 Months Ended							3 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
Compensation Programs (Narrative) (Details) (USD $)	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2009	Sep. 30, 2011 2008 [Member]	Sep. 30, 2011 2008 [Member] Performance-Based Stock Awards [Member]	Sep. 30, 2011 2009 [Member]	Sep. 30, 2011 2009 [Member] Performance-Based Stock Awards [Member]	Sep. 30, 2011 2010 [Member]	Sep. 30, 2011 2010 [Member] Performance-Based Stock Awards [Member]	Sep. 30, 2011 2011 [Member]	Sep. 30, 2011 Annual Incentive Compensation [Member]	Sep. 30, 2011 Annual Incentive Compensation [Member]	Dec. 31, 2010 Annual Incentive Compensation [Member]	Sep. 30, 2011 Stock Awards Activity [Member]	Sep. 30, 2011 Stock Awards Activity [Member]	Sep. 30, 2011 Long Term Equity Based Awards [Member]	Sep. 30, 2011 Option Awards [Member]	Sep. 30, 2011 Option Awards [Member]	Sep. 30, 2011 Other Benefit Programs [Member]	Sep. 30, 2011 Other Benefit Programs [Member]
Share Based Compensation Programs [Line Items]
Total Grants	0	0	30,000	225,000	140,658	225,000	110,917	60,000	128,766	72,000
Expenses related to compensation											$ 1,400,000	$ 4,100,000		$ 469,000	$ 1,349,000			$ 3,000	$ 124,000	$ 367,000
Expiration date of grant	July 1, 2014				2015		2016		2017
Common shares for future issuance	1,180,441
Percentage of investment capital, maximum	10.00%											10.00%	8.00%			8.00%
Performance threshold multiplier, basis points												50
Number of years for average long-term investment capital												10				10
Spread over 10-year U.S. treasury rate (basis points)												200				200
Share awards vesting period (in years)																three		ten
Common stock dividend payable	37,676,000	27,401,000												220,000	220,000
Weighted average remaining contractual term, years															1.6			5.68
Total of unrecognized compensation costs for unvested option awards														3,500,000	3,500,000
Strike price			$ 11.69
Grant date fair value per share			$ 1.52
Volatility factors for years			51.00%
Dividend yields for years			14.00%
Risk-free rates for years			$ 1.70%
Exercisable option awards exercised to date																	256,250	256,250
Weighted average exercise price																	$ 10.71	$ 10.71
Aggregate intrinsic value of stock options																	286,000	286,000
Intrinsic value of stock options exercised																	$ 104,000	$ 129,000
Compensation plan of voluntary contribution																				50.00%
Compensation plan of voluntary contribution, maximum																				6.00%
Compensation plan of voluntary contribution, minimum																				3.00%