Income per Common Share of the Trust (Tables)

12 Months Ended

Dec. 31, 2012

Income per Common Share of the Trust [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	2012					2011
	Income (Numerator)		Weighted Average Shares (Denominator)	Per Share		Income (Numerator)		Weighted Average Shares (Denominator)	Per Share
Basic income from continuing operations
Income from continuing operations net of noncontrolling interest	$	123,945	116,863	$	1.06	$	115,653	114,755	$	1.00
Dilutive shares for long-term compensation plans	—		831			—		748
Diluted income from continuing operations
Income from continuing operations net of noncontrolling interest	123,945		117,694	$	1.06	115,653		115,503	$	1.00
Basic income from discontinued operations
Discontinued operations net of noncontrolling interest	13,491		116,863	$	0.12	68,346		114,755	$	0.60
Dilutive shares for long-term compensation plans	—		831			—		748
Diluted income from discontinued operations
Discontinued operations net of noncontrolling interest	13,491		117,694	$	0.11	68,346		115,503	$	0.59
Basic income per common share
Net income available to common shareholders	137,436		116,863	$	1.18	183,999		114,755	$	1.60
Dilutive shares for long-term compensation plans	—		831			—		748
Diluted income per common share
Net income available to common shareholders	$	137,436	117,694	$	1.17	$	183,999	115,503	$	1.59

	2010
	Income (Numerator)		Weighted Average Shares (Denominator)	Per Share
Basic income from continuing operations
Income from continuing operations net of noncontrolling interest	$	104,522	112,924	$	0.92
Dilutive shares for long-term compensation plans	—		682
Diluted income from continuing operations
Income from continuing operations net of noncontrolling interest	104,522		113,606	$	0.91
Basic income from discontinued operations
Discontinued operations net of noncontrolling interest	23,240		112,924	$	0.21
Dilutive shares for long-term compensation plans	—		682
Diluted income from discontinued operations
Discontinued operations net of noncontrolling interest	23,240		113,606	$	0.21
Basic income per common share
Net income available to common shareholders	127,762		112,924	$	1.13
Dilutive shares for long-term compensation plans	—		682
Diluted income per common share
Net income available to common shareholders	$	127,762	113,606	$	1.12