Supplemental Disclosure to Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Cash Flow Information [Abstract]
Write-off of fully depreciated/amortized property and deferred costs	$ 26,609	$ 26,349
Write-off of depreciated/amortized property and deferred costs due to sale	13,127	34,513
Write-off of costs related to early debt extinguishment	0	109
Redemption of noncontrolling interests - common units	27	132
Unrealized gain (loss) on cash flow hedge	366	(1,132)
Changes in accrued development capital expenditures	18,255	(7,522)
Capitalized equity-based compensation	$ 877	$ 980