CONDENSED CONSOLIDATED STATEMENT OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Non-Controlling Interests
Beginning Balance at Dec. 31, 2017	$ 860,630	$ 392	$ 454,286	$ 325,794	$ 80,158
Beginning Balance (in shares) at Dec. 31, 2017		39,085
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,588			8,328	4,260
Cash contributions from members of consolidated entities	4,062				4,062
Cash distributions to members of consolidated entities	(17,106)				(17,106)
Stock Repurchased During Period, Shares		(205)
Stock Repurchased During Period, Value	(5,000)	$ (2)	(4,998)
Shares remitted to Company to satisfy employee tax obligations	(4,696)	$ (2)	(4,694)
Shares remitted to Company to satisfy employee tax obligations (in shares)		(186)
Stock based compensation expense	3,181	$ 5	3,176
Stock based compensation expense (in shares)		577
Ending Balance at Mar. 31, 2018	853,659	$ 393	447,770	334,122	71,374
Ending Balance (in shares) at Mar. 31, 2018		39,271
Beginning Balance at Dec. 31, 2018	1,014,327	$ 387	445,545	417,390	151,005
Beginning Balance (in shares) at Dec. 31, 2018		38,722
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,134			8,119	7,015
Cash contributions from members of consolidated entities	1,389				1,389
Cash distributions to members of consolidated entities	(11,058)				(11,058)
Shares remitted to Company to satisfy employee tax obligations	(2,356)	$ (1)	(2,355)
Shares remitted to Company to satisfy employee tax obligations (in shares)		(166)
Stock based compensation expense	2,765	$ 2	2,763
Stock based compensation expense (in shares)		281
Ending Balance at Mar. 31, 2019	$ 1,020,201	$ 388	$ 445,953	$ 425,509	$ 148,351
Ending Balance (in shares) at Mar. 31, 2019		38,837