Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 76,907	$ 67,925	$ 56,915
Other comprehensive income:
Change in unrealized net gain on available-for-sale securities	(1,455)	13,124	316
Change in value of interest rate cap	0	(189)	0
Comprehensive income	$ 75,452	$ 80,860	$ 57,231