Earnings Per Common Share Calculation of numerator and denominator in eps table (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share Disclosure [Line Items]
Stockholders' Equity Note, Stock Split	On June 25, 2013, we announced a two-for-one split, to be effected by and in the form of a stock dividend, to be paid on July 15, 2013. On July 15, 2013, each common shareholder of record on July 5, 2013, received one additional share of common stock for each share held.
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ 43,890	$ 36,442
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	(3,481)	(3,133)
Net Income (Loss) Available to Common Stockholders, Basic	38,099	35,024
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	3,695
Amounts allocated to dilutive securities	3,481	3,133
Net income (loss) available for Common Shares – fully diluted	41,580	38,157
Weighted average Common Shares outstanding – basic	83,116	83,026
Employee stock options and restricted shares	602	576
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock	7,635	7,458
Weighted average Common Shares outstanding - fully diluted	91,353	91,060
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.46	$ 0.38
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	$ 0.00	$ 0.04
Net income available for Common Shares	$ 0.46	$ 0.42
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.46	$ 0.38
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.00	$ 0.04
Net income available for Common Shares	$ 0.46	$ 0.42
Stockholders' Equity Note, Stock Split, Conversion Ratio	2
Cumulative Series C Six Point Seven Five Percent Redeemable Perpetual Preferred Stock [Member]
Earnings Per Share Disclosure [Line Items]
Redeemable Preferred Stock Dividends	(2,310)	(2,311)
Segment, Continuing Operations [Member]
Earnings Per Share Disclosure [Line Items]
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	(3,481)	(2,802)
Net Income (Loss) Available to Common Stockholders, Basic	38,099	31,329
Amounts allocated to dilutive securities	3,481	2,802
Net income (loss) available for Common Shares – fully diluted	$ 41,580	$ 34,131