Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 18,847	$ 13,594	$ 35,323	$ 23,874
Other comprehensive income:
Change in market value of available-for-sale securities	9,766	12,796	35,766	6,165
Reclassification adjustment for net gain on sale of available-for-sale securities, net	0	(742)	0	(742)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(11,184)	(11,738)	(11,005)	(8,781)
Other comprehensive income (loss)	(1,418)	316	24,761	(3,358)
Total comprehensive income	$ 17,429	$ 13,910	$ 60,084	$ 20,516