Consolidated Condensed Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Net income	$ 11,982	$ 20,381	$ 62,343	$ 71,530
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 $77 and $83 for the three months ended September 30, 2012 and 2011, and $216 and $187 for the nine months ended September 30, 2012 and 2011	142	155	401	348
Unrealized net holding gain on securities available-for-sale, net of income taxes of $464 and $4,923 for the three months ended September 30, 2012 and 2011, and of $790 and $345 for the nine months ended September 30, 2012 and 2011.	864	9,144	1,468	644
Other comprehensive income (loss)	1,006	9,299	2,281	992
Comprehensive income	$ 12,988	$ 29,680	$ 64,624	$ 72,522