Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 15,244	$ 14,162
Other comprehensive income:
Change in unrealized net gain on available-for-sale securities	1,841	3,254
Change in value of interest rate cap	42	0
Comprehensive income	$ 17,127	$ 17,416