STATEMENTS OF CHANGES IN CONSOLIDATED SHAREHOLDERS' EQUITY (Unaudited) (USD $) In Thousands	Total	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Treasury Stock
Beginning Balance at Dec. 31, 2012	$ 1,279,345	$ 55,057	$ 732,069	$ 787,015	$ 85,588	$ (380,384)
Total comprehensive income (loss)	(42,945)			64,870	(107,815)
Cash dividends	(17,440)			(17,440)
Purchase of treasury stock	(1,750)					(1,750)
Issuance of equity awards	450		(2,466)			2,916
Recognition of equity based compensation	4,096		4,096
Net tax benefit related to equity compensation plans	503		503
Sale of treasury stock	302		198			104
Exercise of stock options	3,911		2,056			1,855
Ending Balance at Jun. 30, 2013	1,226,472	55,057	736,456	834,445	(22,227)	(377,259)
Beginning Balance at Dec. 31, 2013	1,506,065	55,057	882,407	884,630	(32,640)	(283,389)
Total comprehensive income (loss)	107,626			58,085	49,541
Cash dividends	(20,447)			(20,447)
Purchase of treasury stock	(3,165)					(3,165)
Issuance of equity awards	470		(3,395)			3,865
Recognition of equity based compensation	4,733		4,733
Net tax benefit related to equity compensation plans	1,202		1,202
Sale of treasury stock	459		300			159
Exercise of stock options	4,399		1,839			2,560
Ending Balance at Jun. 30, 2014	$ 1,601,342	$ 55,057	$ 887,086	$ 922,268	$ 16,901	$ (279,970)