CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2009	$ 369,055	$ 997	$ 189,900	$ 527,876	$ (328,154)	$ (21,564)
Balance (in shares) at Dec. 31, 2009		99,701
Increase (Decrease) in Stockholders' Equity
Net income	156,959			156,959
Recognition of equity compensation	40,338		40,319	19
Issuance of nonvested shares and other			(37,631)		37,631
Dividends accrued, $2.03, $0.85 and $0.77 per share for the year ended 2012, 2011 and 2010 respectively	(66,041)			(66,041)
Exercise of stock options	13,057		2,726		10,331
Excess tax benefits from share-based payment arrangements	6,128		6,128
Repurchase of common stock	(65,872)				(65,872)
Unrealized appreciation (depreciation) on available for sale investment securities	3,493					3,493
Valuation allowance on investment securities' deferred tax asset	963					963
Pension and postretirement benefits	1,061					1,061
Reclassification for amounts included in net income	(1,980)					(1,980)
Balance at Dec. 31, 2010	457,161	997	201,442	618,813	(346,064)	(18,027)
Balance (in shares) at Dec. 31, 2010		99,701
Increase (Decrease) in Stockholders' Equity
Net income	175,459			175,459
Recognition of equity compensation	46,473		46,457	16
Issuance of nonvested shares and other			(40,442)		40,442
Dividends accrued, $2.03, $0.85 and $0.77 per share for the year ended 2012, 2011 and 2010 respectively	(73,007)			(73,007)
Exercise of stock options	5,080		949		4,131
Excess tax benefits from share-based payment arrangements	8,020		8,020
Repurchase of common stock	(65,463)				(65,463)
Unrealized appreciation (depreciation) on available for sale investment securities	(3,635)					(3,635)
Valuation allowance on investment securities' deferred tax asset	(2,955)					(2,955)
Pension and postretirement benefits	(22,062)					(22,062)
Reclassification for amounts included in net income	(1,428)					(1,428)
Balance at Dec. 31, 2011	523,643	997	216,426	721,281	(366,954)	(48,107)
Balance (in shares) at Dec. 31, 2011		99,701
Increase (Decrease) in Stockholders' Equity
Net income	150,952			150,952
Recognition of equity compensation	49,993		49,937	56
Issuance of nonvested shares and other			(43,106)		43,106
Dividends accrued, $2.03, $0.85 and $0.77 per share for the year ended 2012, 2011 and 2010 respectively	(173,866)			(173,866)
Exercise of stock options	105		(27)		132
Excess tax benefits from share-based payment arrangements	6,791		6,791
Repurchase of common stock	(48,688)				(48,688)
Unrealized appreciation (depreciation) on available for sale investment securities	5,444					5,444
Valuation allowance on investment securities' deferred tax asset	2,024					2,024
Pension and postretirement benefits	(4,157)					(4,157)
Reclassification for amounts included in net income	(2,001)					(2,001)
Balance at Dec. 31, 2012	$ 510,240	$ 997	$ 230,021	$ 698,423	$ (372,404)	$ (46,797)
Balance (in shares) at Dec. 31, 2012		99,701