Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 50,338	$ 43,191
Unrealized loss on derivatives qualifying as hedges
Unrealized loss on cash flow hedge, net of tax of $0 and $3 for 2012 and 2011, respectively	0	(5)
Less: reclassification adjustment for loss on cash flow hedge included in net income, net of tax of $0 and $(25) for 2012 and 2011, respectively	0	44
Unrealized gain on available for sale securities
Unrealized gain on securities, net of tax of $(5) and $0 for 2012 and 2011, respectively	4	3
Less: reclassification adjustment for gain on sale of securities included in net income, net of tax of $0 and $0 for 2012 and 2011, respectively	0	(1)
Other comprehensive income	4	41
Comprehensive income	$ 50,342	$ 43,232