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				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator for basic and diluted earnings per share:
Net income	$ 10,444	$ 14,043	$ 10,571	$ 8,723	$ 24,488	$ 19,294
Net income attributable to non-controlling interests	(63)		(2,620)		(147)	(5,214)
Less: net income allocated to unvested restricted common stock and RSUs	(77)		(112)		(207)	(267)
Net income available for common stockholders: basic	10,304		7,839		24,134	13,813
Less: net income attributable to non-controlling interests	63		2,620		147	5,214
Net income available for common stockholders: diluted	$ 10,367		$ 10,459		$ 24,281	$ 19,027
Denominator for basic and diluted earnings per share:
Weighted average common shares outstanding (in shares)	92,054,919		57,825,460		91,430,110	51,932,547
Less: weighted average number of shares of unvested restricted common stock (in shares)	(450,522)		(721,784)		(466,710)	(727,814)
Weighted average shares outstanding used in basic net income per share (in shares)	91,604,397		57,103,676		90,963,400	51,204,733
Effects of dilutive securities:
Weighted average shares outstanding used in diluted net income per share (in shares)	92,483,898		76,665,905		91,908,098	70,686,969
Operating Partnership Unit
Effects of dilutive securities:
Dilutive securities (in shares)	553,847		19,056,552		553,847	19,056,552
Unvested Restricted Common Stock and RSUs
Effects of dilutive securities:
Dilutive securities (in shares)	325,654		505,677		390,851	425,684