Consolidated Statements Of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2009	$ 1,190,843	$ 2,948	$ (1,141)	$ 1,175,641	$ 13,395
Balance (in shares) at Dec. 31, 2009		294,861,000
Dividends paid in cash	(182,814)			(182,814)
Stock based compensation	4,030		4,030
Net earnings	265,356			265,356
Other comprehensive income (loss)	5,097				5,097
Balance at Dec. 31, 2010	1,282,512	2,948	2,889	1,258,183	18,492
Balance (in shares) at Dec. 31, 2010		294,861,000
Dividends paid in cash	(191,741)			(191,741)
Stock options exercised	8,939	5	8,934
Stock options exercised (in shares)		397,000
Stock based compensation	4,050		4,050
Excess tax benefits from stock based compensation	983		983
Net earnings	357,929			357,929
Other comprehensive income (loss)	(3,696)				(3,696)
Balance at Dec. 31, 2011	1,458,976	2,953	16,856	1,424,371	14,796
Balance (in shares) at Dec. 31, 2011	295,258,674	295,258,000
Dividends paid in cash	(367,306)			(367,306)
Stock options exercised	29,644	13	29,631
Stock options exercised (in shares)		1,306,000
Stock based compensation	4,800		4,800
Excess tax benefits from stock based compensation	10,149		10,149
Net earnings	420,536			420,536
Other comprehensive income (loss)	3,561				3,561
Balance at Dec. 31, 2012	$ 1,560,360	$ 2,966	$ 61,436	$ 1,477,601	$ 18,357
Balance (in shares) at Dec. 31, 2012	296,564,382	296,564,000