Income per Common Share of the Trust (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income per Common Share of the Trust [Abstract]
Income from continuing operations net of noncontrolling interest	$ 29,014	$ 26,848	$ 54,262	$ 49,751
Weighted Average Number of Shares Outstanding, Basic	147,012,000	120,081,000	146,749,000	119,416,000
Income from Continuing Operations, Per Basic Share	$ 0.20	$ 0.22	$ 0.37	$ 0.42
Dilutive shares for long-term compensation plans	762,000	830,000	695,000	813,000
Weighted Average Number of Shares Outstanding, Diluted	147,774,000	120,911,000	147,444,000	120,229,000
Income from Continuing Operations, Per Diluted Share	$ 0.20	$ 0.22	$ 0.37	$ 0.42
Income from Discontinued Operations, Net of Tax, Attributable to Parent	235	13,261	46,887	61,597
Income from Discontinued Operations, Net of Tax, Per Basic Share	$ 0.00	$ 0.11	$ 0.32	$ 0.51
Income from discontinued operations	$ 0.00	$ 0.11	$ 0.32	$ 0.51
Net income available to common shareholders	$ 29,249	$ 40,109	$ 101,149	$ 111,348
Earnings Per Share, Basic	$ 0.20	$ 0.33	$ 0.69	$ 0.93
Earnings Per Share, Diluted	$ 0.20	$ 0.33	$ 0.69	$ 0.93
Dilutive Shares, Shares Issued, Shares Acquired on Exchange [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	750,000	625,000	750,000	773,000
Stock Issued During Period, Shares, Stock Options Exercised	42,000		43,000		504,000