Statements of Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Stockholders' Equity, Total [Member]	Noncontrolling Interest
Beginning Balance at Jan. 01, 2012	$ 1,038,521	$ 852	$ 727,297	$ 507,170	$ 1,930	$ (214,031)		$ 15,303
Beginning Balance, Shares at Jan. 01, 2012		61,181,000				24,004,000
Proceeds from stock options exercised	9,276	6	9,270
Proceeds from stock options exercised, Shares		593,000
Tax benefit related to equity compensation	621		621
Stock based compensation expense	2,539		2,539
Restricted stock granted	0	3	(3)
Restricted stock granted, Shares		315,000
Retirement of common stock	(1,036)	(1)	(628)	(407)
Retirement of common stock, Shares		(58,000)
Restricted stock cancelled	0
Restricted stock cancelled, Shares		(28,000)
Amortization of restricted stock	4,449		4,449
Dividends - Cash	(102,435)			(102,435)
Dividends - Stock	0		(105,784)	274,402		(168,618)
Dividends - Stock, Shares		9,689,000				(9,689,000)
Purchase of treasury shares	(8,666)					(8,666)
Purchase of treasury shares, Shares		298,000				298,000
Re-issuance of treasury shares (ESPP)	460		5	(9)		464
Re-issuance of treasury shares (ESPP), Shares		(23,000)				23,000
Increase in Ownership of Subsidiary (MCF)	(25,138)		(17,053)					(8,085)
Other adjustments to Additional Paid-In Capital	(51)		(51)
Distribution to noncontrolling interest	(5,758)							(5,758)
Net income (loss)	133,898			134,750				(852)
Other comprehensive income (loss), net of tax	624				740			(116)
Ending Balance at Dec. 31, 2012	1,047,304	860	832,230	264,667	2,670	(53,615)		492
Ending Balance, Shares at Dec. 31, 2012		71,417,000				14,590,000
Proceeds from stock options exercised	5,425	3	5,422
Proceeds from stock options exercised, Shares		318,000
Tax benefit related to equity compensation	2,197		2,197
Stock based compensation expense	1,307		1,307
Restricted stock granted	0	3	(3)
Restricted stock granted, Shares		345,000
Restricted stock cancelled	0
Restricted stock cancelled, Shares		(8,000)
Amortization of restricted stock	6,582		6,582
Dividends - Cash	(147,156)			(147,156)
Dividends - Stock, Shares	9,688,568
Purchase of treasury shares	0	0	0			0
Purchase of treasury shares, Shares		0				0
Re-issuance of treasury shares (ESPP)	319		283	0		36
Re-issuance of treasury shares (ESPP), Shares		(10,000)				(10,000)
Net income (loss)	115,197			115,135				62
Other comprehensive income (loss), net of tax	(7,199)				(7,099)			(100)
Ending Balance at Dec. 31, 2013	1,023,976	866	848,018	232,646	(4,429)	(53,579)		454
Ending Balance, Shares at Dec. 31, 2013		72,082,000				14,580,000
Proceeds from stock options exercised	7,281	4	7,277
Proceeds from stock options exercised, Shares	386,000	386,000
Tax benefit related to equity compensation	2,035		2,035
Stock based compensation expense	1,161		1,161
Restricted stock granted	0	3	(3)
Restricted stock granted, Shares		306,000
Retirement of common stock		(146)	(54,826)	0		54,972	0
Retirement of common stock, Shares		0				(14,618,000)
Restricted stock cancelled	0	0
Restricted stock cancelled, Shares		(23,000)
Amortization of restricted stock	7,748		7,748
Dividends - Cash	(170,234)			(170,234)
Purchase of treasury shares			(428)			(1,416)	(1,844)
Purchase of treasury shares, Shares		54,000				43,000
Issuance of common stock (ATM)		15	54,710				54,725
Issuance of common stock (ATM), Shares		1,483,000
Re-issuance of treasury shares (ESPP)	387		364	0		23
Re-issuance of treasury shares (ESPP), Shares		(11,000)				(5,000)
Net income (loss)	143,840			143,930				(90)
Other comprehensive income (loss), net of tax	(23,082)				(23,032)			(50)
Ending Balance at Dec. 31, 2014	$ 1,045,993	$ 742	$ 866,056	$ 206,342	$ (27,461)	$ 0		$ 314
Ending Balance, Shares at Dec. 31, 2014		74,191,000				0