Income per Common Share of the Trust (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income per Common Share of the Trust [Abstract]
Income from continuing operations net of noncontrolling interest	$ 25,250	$ 22,908
Weighted Average Number of Shares Outstanding, Basic	146,425,000	118,688,000
Income from Continuing Operations, Per Basic Share	$ 0.17	$ 0.19
Dilutive shares for long-term compensation plans	670,000	844,000
Weighted Average Number of Shares Outstanding, Diluted	147,095,000	119,532,000
Income from Continuing Operations, Per Diluted Share	$ 0.17	$ 0.19
Income from Discontinued Operations, Net of Tax, Attributable to Parent	46,650	48,331
Income from Discontinued Operations, Net of Tax, Per Basic Share	$ 0.32	$ 0.41
Discontinued operations net of noncontrolling interest, Per Diluted Share	$ 0.32	$ 0.41
Net Income Available to Common Stockholders, Basic	$ 71,900	$ 71,239
Earnings Per Share, Basic	$ 0.49	$ 0.60
Earnings Per Share, Diluted	$ 0.49	$ 0.60
Dilutive Shares, Shares Issued, Shares Acquired on Exchange [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,247,000	992,000
Stock Issued During Period, Shares, Stock Options Exercised	1,000		504,000