Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 17,692	$ 13,824	$ 49,764	$ 41,125
Other comprehensive income:
Change in unrealized net gain on available-for-sale securities	(1,563)	(2,425)	2,644	(996)
Change in value of interest rate cap	(30)	0	(183)	0
Comprehensive income	$ 16,099	$ 11,399	$ 52,225	$ 40,129