Consolidated Condensed 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
Statement of Other Comprehensive Income [Abstract]
Net income	$ 18,886	$ 28,953	$ 50,361	$ 51,149
Other comprehensive income, net of tax
Change in funded status of pension plan, net of income taxes of $222	0	0	412
Unrealized net holding gain on cash flow hedge, net of income taxes of $139 and $104	146	60	259	193
Unrealized net holding gain (loss) on securities available-for-sale, net of income tax benefit of $326 and $(4,578)	2,806	(2,129)	604	(8,500)
Other comprehensive income (loss)	2,952	(2,069)	1,275	(8,307)
Comprehensive income	$ 21,838	$ 26,884	$ 51,636	$ 42,842