Net Income Per Class A Share - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Income from continuing operations	$ 67,769		$ 48,059		$ 117,917	$ 106,228
Net income	67,769	$ 66,364	48,059	$ 58,169	134,133	106,228
Income from continuing operations attributable to noncontrolling interest	(45,911)		(34,913)		(80,886)	(77,252)
Income from continuing operations attributable to Class A shares - basic and diluted	21,858		13,146		37,031	28,976
Income from discontinued operations	0		0		16,216	0
Income from discontinued operations attributable to noncontrolling interest	0		0		(11,434)	0
Income from discontinued operations attributable to Class A shares - basic and diluted	0		0		4,782	0
Net income attributable to Class A shares - basic and diluted	$ 21,858		$ 13,146		$ 41,813	$ 28,976
Denominator:
Basic weighted average Class A shares outstanding (in shares)	91,011,559		70,993,091		87,544,627	70,982,243
Effect of dilutive shares for diluted net income per Class A share (in shares)	196,839		191,905		228,087	176,342
Weighted average shares for diluted net income per Class A share (in shares)	91,208,398		71,184,996		87,772,714	71,158,585