Earnings Per OP Unit of MAALP Statement (details) (Limited Partner [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share Disclosure [Line Items]
Weighted Average Number of Limited Partnership and General Partnership Unit Outstanding, Basic and Diluted	79,156		44,398		79,090	44,234
Effect of dilutive securities	0	[1]	0	[1]	162	60
Weighted Average Number of Shares Outstanding, Diluted	79,156		44,398		79,252	44,294
Calculation of Basic Earnings Per Unit [Member]
Earnings Per Share Disclosure [Line Items]
Income from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ 29,302		$ 16,214		$ 36,000	$ 36,437
Gain on Disposition of Property Plant Equipment	3,658		0		6,222	0
(Loss) Gain on Disposition of Other Assets	(22)		0		535	0
Income from continuing operations allocated to unvested restricted shares	(63)		(14)		(79)	(32)
Adjusted Income from Continuing Operations Available for Common Unitholders	32,875		16,200		42,678	36,405
Income from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	448		33,286		6,343	34,856
Income from discontinued operations allocated to unvested restricted shares	(1)		(29)		0	0
Adjusted Income from Discontinued Operations Available for Common Unitholders	447		33,257		6,343	34,856
Basic Earnings Per Unit	$ 0.42		$ 1.11		$ 0.62	$ 1.61
Calculation of Diluted Earnings Per Unit [Member]
Earnings Per Share Disclosure [Line Items]
Income from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	29,302		16,214		36,000	36,437
Gain on Disposition of Property Plant Equipment	3,658		0		6,222	0
(Loss) Gain on Disposition of Other Assets	(22)		0		535	0
Income from continuing operations allocated to unvested restricted shares	(63)	[1]	(14)	[1]	0	0
Adjusted Income from Continuing Operations Available for Common Unitholders	32,875		16,200		42,757	36,437
Income from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	448		33,286		6,343	34,856
Income from discontinued operations allocated to unvested restricted shares	(1)	[1]	(29)	[1]	0	0
Adjusted Income from Discontinued Operations Available for Common Unitholders	$ 447		$ 33,257		$ 6,343	$ 34,856
Diluted Earnings Per Unit	$ 0.42		$ 1.11		$ 0.62	$ 1.61

[1] (1) Dilutive securities and the related income are not included in the diluted earnings per unit calculations as they were not dilutive.