Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 31,359	$ 24,640	$ 50,504	$ 41,345
Other comprehensive income (loss):
Change in unrealized gain (loss) on valuation of interest rate swap agreements	(14,367)	(10,864)	(12,973)	(30,235)
Other comprehensive income (loss)	(14,367)	(10,864)	(12,973)	(30,235)
Comprehensive income (loss)	16,992	13,776	37,531	11,110
Net income attributable to non-controlling interests and private perpetual preferred unitholders	(14,775)	(13,551)	(23,935)	(22,828)
Other comprehensive (income) loss attributable to non-controlling interests	6,742	5,900	6,084	16,540
Comprehensive income (loss) attributable to common stockholders	$ 8,959	$ 6,125	$ 19,680	$ 4,822