Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2012

Shareholders' Equity [Abstract]

Schedule of Taxability of Common Shares [Table Text Block]

	2012		2011		2010
Ordinary dividend	$	1.5036	$	1.4300	$	1.4812
Qualified dividend	—		—		—
Capital gain - 15%	—		0.1708		—
IRC Sec 1250 unrecapture gain - 25%	0.0164		0.2992		0.0128
Return of capital	0.3800		—		0.4060
Total	$	1.9000	$	1.9000	$	1.9000

Temporary Equity [Table Text Block]

ISSUE	AMOUNT		UNITS	LIQUIDATION PREFERENCE		DIVIDEND RATE		REDEEMABLE AS OF	EXCHANGEABLE AFTER
	(in 000’s)
Series E	$	20,000	400		$50	7.00	%	6/16/2010	6/16/15 into Series E Cumulative Redeemable Preferred Shares of the Trust
Series F	$	17,500	350		$50	6.65	%	6/30/2010	12/12/15 into Series F Cumulative Redeemable Preferred Shares of the Trust
Series G	$	27,000	540		$50	6.70	%	12/15/2011	12/15/16 into Series G Cumulative Redeemable Preferred Shares of the Trust

Preferred Unit Distributions [Table Text Block]

	2012	2011	2010
Distributions (in millions)	$9.9	$21.0	$21.0
Distribution per unit:
Series B	$0.45	$1.86	$1.86
Series E	$3.50	$3.50	$3.50
Series F	$1.43	$3.33	$3.33
Series G	$3.35	$3.35	$3.35
Series H	$0.77	$1.85	$1.85