Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 16,828	$ 13,139	$ 32,072	$ 27,301
Other comprehensive income:
Change in unrealized net gain on available-for-sale securities	2,366	(1,825)	4,207	1,429
Change in value of interest rate cap	(195)	0	(153)	0
Comprehensive income	$ 18,999	$ 11,314	$ 36,126	$ 28,730