Net Income Per Class A Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								8 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income (loss) attributable to Class A shareholders	$ 12,394	$ 10,591	$ 6,953	$ 0	$ 0	$ 0	$ 0	$ 0		$ 29,938	$ 0	$ 0
Denominator:
Basic weighted average Class A shares outstanding										57,502,158,000
Basis net income per Class A share (in usd per share)	$ 0.22	$ 0.18	$ 0.12							$ 0.52
Numerator:
Net income (loss) attributable to Class A shareholders	$ 12,394	$ 10,591	$ 6,953	$ 0	$ 0	$ 0	$ 0	$ 0		$ 29,938	$ 0	$ 0
Denominator:
Basic weighted average Class A shares outstanding										57,502,158,000
Effect of dilutive shares for diluted net income per Class A share									249,331,000
Weighted average shares for diluted net income per Class A share										57,751,489,000
Diluted net income per Class A share (in usd per share)	$ 0.21	$ 0.18	$ 0.12							$ 0.52
Class A Shares
Numerator:
Net income (loss) attributable to Class A shareholders									$ 29,938
Denominator:
Basic weighted average Class A shares outstanding									57,502,158,000
Basis net income per Class A share (in usd per share)									$ 0.52
Numerator:
Net income (loss) attributable to Class A shareholders									$ 29,938
Denominator:
Basic weighted average Class A shares outstanding									57,502,158,000
Weighted average shares for diluted net income per Class A share									57,502,158,000
Stock Compensation Plan
Denominator:
Potentially dilutive shares (in shares)									0