Earnings Per Share - Calculation of EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income attributable to common stockholders	$ 134,053	$ 11,529	$ 28,960	$ 8,945	$ 23,994	$ 31,443	$ 28,009	$ 4,338	$ 183,487	$ 87,784	$ 91,877
Distributions declared on unvested share-based compensation									(132)	0	0
Net income available to common stockholders									$ 183,355	$ 87,784	$ 91,877
Denominator:
Weighted-average number of common shares outstanding—basic (in shares)									202,009,750	205,462,911	200,784,450
Effect of dilutive securities:
Unvested restricted common stock (in shares)									156,146	215,655	188,759
Shares related to unvested PSUs (in shares)									575,734	452,584	548,259
Weighted-average number of common shares outstanding—diluted (in shares)									202,741,630	206,131,150	201,521,468
Net income per share available to common stockholders - basic (in dollars per share)	$ 0.67	$ 0.06	$ 0.14	$ 0.04	$ 0.12	$ 0.15	$ 0.14	$ 0.02	$ 0.91	$ 0.43	$ 0.46
Net income per share available to common stockholders - diluted (in dollars per share)	$ 0.66	$ 0.06	$ 0.14	$ 0.04	$ 0.12	$ 0.15	$ 0.14	$ 0.02	$ 0.90	$ 0.43	$ 0.46