Accounting for the Impairment or Disposal of Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Gain on property dispositions	$ 0	$ 139	$ 0	$ 46,254
Net income	0	295	0	48,143
Discontinued Operations [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues	0	(29)	0	4,719
Operating expenses	0	183	0	(2,312)
Interest and other income	0	2	0	39
Interest expense	0	0	0	(557)
Depreciation and amortization	0	0	0	0
Income before gain on property dispositions	0	156	0	1,889
Gain on property dispositions	0	139	0	46,254
Net income	$ 0	$ 295	$ 0	$ 48,143