Consolidated Condensed Statements Of Changes In Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Treasury Stock At Cost [Member]	Accumulated Other Comprehensive Income (loss) [Member]
Balance at Dec. 31, 2011		$ 98,146	$ 305,499	$ 424,557	$ (77,007)	$ (8,831)
Net Income	62,343			62,343
Other comprehensive income, net of tax:
Change in funded status of pension plan, net of income taxes	(412)					412
Unrealized net holding gain on cash flow hedge, net of income taxes	401					401
Unrealized net holding loss on securities available-for-sale, net of income taxes	1,468					1,468
Cash dividends on common stock at $2.82 per share				(43,445)
Cash payment for fractional shares in dividend reinvestment plan			(2)
Common stock warrant repurchased	(2,843)
Preferred stock repurchased	100,000
Accretion of discount on preferred stock		1,854		(1,854)
Preferred stock dividends				(1,571)
Balance at Sep. 30, 2012		0	302,654	440,030	(77,007)	(6,550)
Balance at Dec. 31, 2012	650,366	0	302,654	441,605	(76,375)	(17,518)
Net Income	59,773			59,773
Other comprehensive income, net of tax:
Change in funded status of pension plan, net of income taxes
Unrealized net holding gain on cash flow hedge, net of income taxes
Unrealized net holding loss on securities available-for-sale, net of income taxes	(33,931)					(33,931)
Cash dividends on common stock at $2.82 per share				(43,461)
Cash payment for fractional shares in dividend reinvestment plan			(2)
Common stock warrant repurchased	0
Balance at Sep. 30, 2013	$ 632,745	$ 0	$ 302,652	$ 457,917	$ (76,375)	$ (51,449)