Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Net income	$ 8,367	$ 3,196	$ 13,817	$ 7,533
Other comprehensive income, net of tax:
Net unrealized gains on available-for-sale securities, net of tax	96	101	35	127
Other comprehensive income	96	101	35	127
Comprehensive income	8,463	3,297	13,852	7,660
Preferred stockholder dividends		(704)		(1,408)
Allocation of comprehensive income to preferred stockholders		(467)	(63)	(1,126)
Comprehensive income attributable to common stockholders	$ 8,463	$ 2,126	$ 13,789	$ 5,126