Summary of Significant Accounting Principles - Reconciliation of Numerator and Denominator used in Computation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator for basic and diluted earnings per share:
Net income	$ 8,723	$ 1,109
Net income attributable to non-controlling interests	(2,594)
Less: net income allocated to unvested restricted common stock	(155)
Net income available for common stockholders: basic	5,974
Net income attributable to non-controlling interests	2,594
Net income available for common stockholders: diluted	$ 8,568
Denominator for basic and diluted earnings per share:
Weighted average common shares outstanding	45,974,158
Less: weighted average number of shares of unvested restricted common stock	(733,911)
Weighted average shares outstanding used in basic net income per share	45,240,247
Effects of dilutive securities:
Weighted average shares outstanding used in diluted net income per share	64,640,054
Operating Partnership Unit
Effects of dilutive securities:
Dilutive securities	19,056,552
Unvested Restricted Common Stock and RSUs
Effects of dilutive securities:
Dilutive securities	343,255