Summary of Significant Accounting Policies - Revision of Previously Issued Income Statement (Details) - USD ($)	3 Months Ended								6 Months Ended	9 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	Jun. 30, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Expenses:
Property operating expenses					$ 27,586,000	$ 56,531,000	$ 52,296,000	$ 37,698,000	$ 89,994,000	$ 146,525,000	$ 80,881,000	$ 174,111,000	$ 190,165,000
Other income (expense):
Income tax benefit (expense)	$ 4,424,000	$ (3,070,000)	$ 0	$ 0	(663,000)	(8,449,000)	(666,000)	0	(666,000)	(9,115,000)	1,354,000	(9,778,000)	0
Income (loss) from continuing operations	2,046,000	20,701,000	32,188,000	1,177,000	(131,779,000)	25,571,000	(39,149,000)	(15,267,000)	(54,416,000)	(29,100,000)	56,112,000	(160,624,000)	(60,438,000)
Net income (loss) before gain on sale of real estate and unconsolidated entity					(141,239,000)	33,185,000	160,571,000		152,356,000	185,286,000	65,803,000	44,047,000	(92,144,000)
Net income (loss)	$ 1,530,000	$ 20,701,000	$ 43,063,000	$ 654,000	$ (121,173,000)	$ 32,121,000	$ 227,160,000	$ (8,215,000)	$ 218,945,000	$ 251,066,000	$ 65,948,000	$ 129,893,000	$ (92,144,000)
Net income (loss) per share of common stock (basic and diluted)
Continuing operations (in dollars per shares)					$ (0.34)	$ 0.08	$ 0.09	$ (0.05)	$ 0.03	$ 0.11	$ 0.17	$ (0.23)	$ (0.18)
Net income (loss) per share (in dollars per shares)	$ 0.01	$ 0.06	$ 0.13	$ 0.00	$ (0.37)	$ 0.10	$ 0.70	$ (0.03)	$ 0.67	$ 0.77	$ 0.20	$ 0.40	$ (0.28)
As Reported
Expenses:
Property operating expenses					$ 27,312,000	$ 56,256,000	$ 52,021,000	$ 37,038,000	$ 89,059,000	$ 145,315,000		$ 172,627,000
Other income (expense):
Income tax benefit (expense)					0	0	0		0	0		0
Income (loss) from continuing operations					(130,842,000)	34,295,000	(38,208,000)	(14,607,000)	(52,815,000)	(18,775,000)		(149,362,000)
Net income (loss) before gain on sale of real estate and unconsolidated entity					(140,302,000)	41,909,000	161,512,000		153,957,000	195,611,000		55,309,000
Net income (loss)					$ (120,236,000)	$ 40,845,000	$ 228,101,000	$ (7,555,000)	$ 220,546,000	$ 261,391,000		$ 141,155,000
Net income (loss) per share of common stock (basic and diluted)
Continuing operations (in dollars per shares)					$ (0.34)	$ 0.11	$ 0.09	$ (0.04)	$ 0.04	$ 0.14		$ (0.20)
Net income (loss) per share (in dollars per shares)					$ (0.37)	$ 0.13	$ 0.70	$ (0.02)	$ 0.68	$ 0.80		$ 0.43
2015 Insurance Reserve | Adjustment
Expenses:
Property operating expenses					$ 274,000	$ 275,000	$ 275,000	$ 660,000	$ 935,000	$ 1,210,000		$ 1,484,000
Other income (expense):
Income tax benefit (expense)					(663,000)	(8,449,000)	(666,000)	0	(666,000)	(9,115,000)		(9,778,000)
Income (loss) from continuing operations					(937,000)	(8,724,000)	(941,000)	(660,000)	(1,601,000)	(10,325,000)		(11,262,000)
Net income (loss) before gain on sale of real estate and unconsolidated entity					(937,000)	(8,724,000)	(941,000)		(1,601,000)	(10,325,000)		(11,262,000)
Net income (loss)					$ (937,000)	$ (8,724,000)	$ (941,000)	$ (660,000)	$ (1,601,000)	$ (10,325,000)		$ (11,262,000)
Net income (loss) per share of common stock (basic and diluted)
Continuing operations (in dollars per shares)					$ 0.00	$ (0.03)	$ 0.00	$ (0.01)	$ (0.01)	$ (0.03)		$ (0.03)
Net income (loss) per share (in dollars per shares)					$ 0.00	$ (0.03)	$ 0.00	$ (0.01)	$ (0.01)	$ (0.03)		$ (0.03)