Consolidated Statement 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, 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	89,105			89,105
Recognition of share-based compensation	24,565		24,565
Issuance of nonvested shares			(31,412)		31,412
Dividends accrued, $0.50 per share	(43,064)			(43,064)
Excess tax benefits from share-based payment arrangements	2,831		2,831
Repurchase of common stock	(29,323)				(29,323)
Unrealized appreciation of available for sale investment securities	2,548					2,548
Valuation allowance on investment securities' deferred tax asset	867					867
Pension and postretirement benefits	1,548					1,548
Reclassification adjustment for amounts included in net income	(1,073)					(1,073)
Balance at Jun. 30, 2012	$ 571,647	$ 997	$ 212,410	$ 767,322	$ (364,865)	$ (44,217)
Balance (in shares) at Jun. 30, 2012		99,701