Condensed Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Dividends declared per share of common stock	$ 0.14	$ 0.18	$ 0.28	$ 0.36
Dividends declared and paid per share of common stock	$ 0.14	$ 0.18	$ 0.28	$ 0.36
Repurchase of Class A common stock, shares		726,539	233,172	726,539
Forfeitures of restricted Class A common stock, shares		144,630	0	144,630
Class A Common Stock [Member]
Equity-based compensation, shares	81,171	100,790	321,506	381,674
Grant of exchangeability and redemption of limited partnership interests, shares	3,879,468	4,687,831	5,700,056	7,475,021
Issuance of Class A common stock (net of costs), shares	46,785	7,025,771	108,427	25,951,473
Repurchase of Class A common stock, shares	0	726,539	233,172	726,539
Issuance of Class A common stock and RSUs for acquisitions, shares	481,232	687,376	499,449	1,004,472
Forfeitures of restricted Class A common stock, shares		144,630		144,630
Class A Common Stock [Member] | Smith Mack [Member]
Issuance of Class A common stock and RSUs for acquisitions, shares	481,232	687,376	499,449	1,004,472
Class A Common Stock [Member] | Partnership Units [Member]
Redemption of FPUs	2,755	75,720	5,055	81,123