Earnings Per Unit (EPU) - Computation of Basic and Diluted EPU (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Income (Loss) from Continuing Operations	$ 8,043	$ 10,145	$ 3,281	$ 4,218	$ 2,284	$ 4,958	$ (1,548)	$ 299	$ 25,687	$ 5,993	$ (25,181)
(Loss) Gain on Sale of Real Estate, Net of Income Tax Provision	(83)	0	0	0	337	221	0	262	(83)	820	3,777
Income from Continuing Operations Allocable to Participating Securities	(32)	(41)	(33)	(21)	(6)	(13)	0	(36)	(83)	0	0
Preferred Unit Distributions	0	0	0	(1,019)	(1,227)	(1,392)	(2,277)	(3,837)	(1,019)	(8,733)	(18,947)
Redemption of Preferred Units	0	0	0	(1,462)	0	(2,121)	(3,546)	0	(1,462)	(5,667)	(1,804)
Income (Loss) from Continuing Operations Available to Unitholders									23,040	(7,587)	(42,155)
Income from Discontinued Operations	11,702	12,073	946	860	19,809	3,559	12,941	(1,689)	25,581	34,620	18,986
Income from Discontinued Operations Allocable to Participating Securities	(47)	(49)	(10)	(10)	(85)	(29)	(42)	0	(92)	(162)	0
Income from Discontinued Operations Attributable to Unitholders									25,489	34,458	18,986
Net Income (Loss) Available	19,662	22,218	4,227	2,597	21,203	5,225	5,570	(4,965)	48,704	27,033	(23,169)
Net Income Allocable to Participating Securities									(175)	(162)	0
Net Income (Loss) Available to Unitholders	$ 19,583	$ 22,128	$ 4,184	$ 2,566	$ 21,112	$ 5,183	$ 5,528	$ (5,001)	$ 48,529	$ 26,871	$ (23,169)
Denominator (In Thousands):
Weighted Average Units—Basic	114,512	114,512	114,278	114,245	114,089	114,089	112,808	105,477	114,388	111,646	96,509
LTIP Unit Awards	287	199	589	539	485	407	0	0	403	0	0
Weighted Average Units - Diluted	114,799	114,711	114,867	114,784	114,574	114,496	112,808	105,477	114,791	111,646	96,509
Basic and Diluted EPU:
Income (Loss) from Continuing Operations Available to Unitholders									$ 0.20	$ (0.07)	$ (0.44)
Income from Discontinued Operations Attributable to Unitholders									$ 0.22	$ 0.31	$ 0.20
Net Income (Loss) Available to Unitholders									$ 0.42	$ 0.24	$ (0.24)