Shareholders' Equity, Noncontrolling Interests and Other Comprehensive Income - Noncontrolling Interest (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				$ 420,866					$ 420,866
Net (income) loss attributable to noncontrolling interests	$ (14,415)	$ 5,786	$ (8,237)	$ (44,950)	$ 1,019	$ (4,328)	$ (58,963)	$ (21,990)	(61,816)	$ (84,262)	$ (81,082)
Conversion of 100,620 Common OP Units to Common Shares by limited partners of the Operating Partnership									0	0	0
Acquisition of noncontrolling interests									(18,379)	(7,970)
Issuance of OP Units to acquire real estate									31,429	0	44,051
Other comprehensive income - unrealized loss on valuation of swap agreements									(646)	(5,061)	(9,061)
Reclassification of realized interest on swap agreements									4,576	5,524	3,776
Noncontrolling interest contributions									295,108	35,489	57,969
Noncontrolling interest distributions and other reductions									(80,769)	(74,950)	(218,152)
Employee Long-term Incentive Plan Unit Awards									13,694	8,644	8,460
Balance	$ 589,548				$ 420,866				589,548	420,866
Payments to noncontrolling interests									$ 105,994	$ 84,610	$ 221,330
Distributions declared (in dollars per share)	$ 0.41	$ 0.25	$ 0.25	$ 0.25	$ 0.50	$ 0.24	$ 0.24	$ 0.24	$ 1.16	$ 1.22	$ 1.23
Limited partners' capital account, units issued and converted (in shares)	351,250				100,620				351,250	100,620	136,128
LTIP Units [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
LTIP units outstanding (in shares)	1,996,388				1,922,623				1,996,388	1,922,623
Series A Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Limited partners' capital account, units issued and converted (in shares)	1,392								1,392
Series C Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A Preferred OP Units (in shares)	141,593								141,593
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				$ 420,866				$ 380,416	$ 420,866	$ 380,416	$ 417,352
Distributions declared of $1.22 per Common OP Unit									(6,753)	(5,983)	(5,085)
Net (income) loss attributable to noncontrolling interests									61,816	84,262	81,082
Conversion of 100,620 Common OP Units to Common Shares by limited partners of the Operating Partnership									(7,892)	(2,451)	(3,181)
Acquisition of noncontrolling interests									(25,925)	(3,561)
Change in control of previously consolidated investment (Note 4)									(75,713)
Acquisition of noncontrolling interests									(25,925)
Issuance of OP Units to acquire real estate									31,429		44,051
Other comprehensive income - unrealized loss on valuation of swap agreements									(331)	(1,014)	(1,247)
Reclassification of realized interest on swap agreements									596	1,935	1,099
Noncontrolling interest contributions									295,108	35,489	57,969
Noncontrolling interest distributions and other reductions									(80,769)	(74,950)	(218,152)
Employee Long-term Incentive Plan Unit Awards									12,768	6,723	6,528
Balance	$ 589,548				$ 420,866				589,548	420,866	380,416
Noncontrolling Interests | Partially-Owned Affiliates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				324,526				286,181	324,526	286,181	368,404
Distributions declared of $1.22 per Common OP Unit									0	0	0
Net (income) loss attributable to noncontrolling interests									56,814	80,426	77,878
Conversion of 100,620 Common OP Units to Common Shares by limited partners of the Operating Partnership									0	0	0
Acquisition of noncontrolling interests										(3,561)
Change in control of previously consolidated investment (Note 4)									0
Acquisition of noncontrolling interests									(25,925)
Issuance of OP Units to acquire real estate									0		0
Other comprehensive income - unrealized loss on valuation of swap agreements									(288)	(897)	(902)
Reclassification of realized interest on swap agreements									373	1,838	984
Noncontrolling interest contributions									295,108	35,489	57,969
Noncontrolling interest distributions and other reductions									(80,769)	(74,950)	(218,152)
Employee Long-term Incentive Plan Unit Awards									0	0	0
Balance	$ 569,839				$ 324,526				$ 569,839	$ 324,526	$ 286,181
Operating Partnership, as General Partner or Managing Member [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A Preferred OP Units (in shares)	3,365,668				2,931,198				3,365,668	2,931,198
Equity Interest Held By Operating Partnership									95.00%	95.00%
Operating Partnership, as General Partner or Managing Member [Member] | Series A Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A Preferred OP Units (in shares)	188				188				188	188	188
Operating Partnership, as General Partner or Managing Member [Member] | Series C Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A Preferred OP Units (in shares)		141,593
Operating Partnership, as General Partner or Managing Member [Member] | Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				96,340				$ 94,235	$ 96,340	$ 94,235	$ 48,948
Distributions declared of $1.22 per Common OP Unit									(6,753)	(5,983)	(5,085)
Net (income) loss attributable to noncontrolling interests									5,002	3,836	3,204
Conversion of 100,620 Common OP Units to Common Shares by limited partners of the Operating Partnership									(7,892)	(2,451)	(3,181)
Acquisition of noncontrolling interests										0
Change in control of previously consolidated investment (Note 4)									(75,713)
Acquisition of noncontrolling interests									0
Issuance of OP Units to acquire real estate									31,429		44,051
Other comprehensive income - unrealized loss on valuation of swap agreements									(43)	(117)	(345)
Reclassification of realized interest on swap agreements									223	97	115
Noncontrolling interest contributions									0	0	0
Noncontrolling interest distributions and other reductions									0	0	0
Employee Long-term Incentive Plan Unit Awards									12,768	6,723	6,528
Balance	$ 19,709				$ 96,340				$ 19,709	96,340	$ 94,235
Fund II [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Additional ownership interest acquired									8.30%
Payments to noncontrolling interests									$ 18,400
Equity Interest Held By Operating Partnership									28.33%
Restatement Adjustment [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				$ (31,800)					$ (31,800)
Net (income) loss attributable to noncontrolling interests	1,600
Balance	(35,700)				$ (31,800)				(35,700)	$ (31,800)
Restatement Adjustment [Member] | Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(35,652)								(35,652)
Restatement Adjustment [Member] | Noncontrolling Interests | Partially-Owned Affiliates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	0								0
Restatement Adjustment [Member] | Operating Partnership, as General Partner or Managing Member [Member] | Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ (35,652)								$ (35,652)