Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	COMMON STOCK (Par Value: $0.01):	PAID-IN CAPITAL IN EXCESS OF PAR:	(ACCUMULATED DEFICIT) RETAINED EARNINGS:	TREASURY STOCK:	ACCUMULATED OTHER COMPREHENSIVE LOSS, NET OF TAX:
Balance at beginning of year at Dec. 31, 2012		$ 4,391	$ 5,327,111	$ 387,534	$ (1,067)	$ (61,705)
Shares issued for restricted stock awards		18	(5,093)		5,075
Net (loss) income	$ 475,547			475,547
Purchase of common stock (448,223; 439,437; and 383,640 shares, respectively)					(5,319)
Other comprehensive (loss) income, net of tax	25,212					25,212
Compensation expense related to restricted stock awards			22,247
Dividends paid on common stock ($1.00 per share in each year)				(440,308)
Exercise of stock options			60	(12)	279
Tax effect of stock plans	1,692		1,692
Balance at end of year at Dec. 31, 2013	5,735,662	4,409	5,346,017	422,761	(1,032)	(36,493)
Shares issued for restricted stock awards		18	(7,073)		7,055
Net (loss) income	485,397			485,397
Purchase of common stock (448,223; 439,437; and 383,640 shares, respectively)					(7,283)
Other comprehensive (loss) income, net of tax	(19,193)					(19,193)
Compensation expense related to restricted stock awards			27,454
Dividends paid on common stock ($1.00 per share in each year)				(442,204)
Exercise of stock options				(82)	142
Tax effect of stock plans	3,225		3,225
Effect of adopting Accounting Standards Update No. 2014-01				(1,303)
Balance at end of year at Dec. 31, 2014	5,781,815	4,427	5,369,623	464,569	(1,118)	(55,686)
Shares issued for restricted stock awards		17	(7,708)		7,691
Net (loss) income	(47,156)			(47,156)
Purchase of common stock (448,223; 439,437; and 383,640 shares, respectively)					(7,020)
Other comprehensive (loss) income, net of tax	(1,335)					(1,335)
Compensation expense related to restricted stock awards			30,205
Dividends paid on common stock ($1.00 per share in each year)				(453,981)
Proceeds from follow-on common stock offering, net		406	629,276
Tax effect of stock plans	2,486		2,486
Balance at end of year at Dec. 31, 2015	$ 5,934,696	$ 4,850	$ 6,023,882	$ (36,568)	$ (447)	$ (57,021)