Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 32,844	$ 80,509	$ 86,477
Other comprehensive (loss) income:
Change in fair value of marketable securities (see Note 5)	0	(2,762)	(5,273)
Change in value of interest rate cap	(1)	(70)	133
Comprehensive income	$ 32,843	$ 77,677	$ 81,337