Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Data [Abstract]

Schedule Of Quarterly Financial Information

	Quarter Ended
	December 31,		September 30,		June 30,		March 31,
	2017		2017		2017		2017
	(in thousands, except per share amounts)
Revenues	$	443,073	$	433,945	$	427,294	$	423,362
Operating income		119,081		117,011		114,590		107,819
Depreciation, accretion, and amortization		(162,643)		(161,907)		(159,520)		(159,030)
Loss from extinguishment of debt, net		—		—		(1,961)		—
Net income		7,660		49,161		9,233		37,600
Net income per common share - basic (1)	$	0.07	$	0.41	$	0.08	$	0.31
Net income per common share - diluted		0.06		0.41		0.08		0.31
	Quarter Ended
	December 31,		September 30,		June 30,		March 31,
	2016		2016		2016		2016
	(in thousands, except per share amounts)
Revenues	$	416,505	$	411,319	$	405,532	$	399,769
Operating income		107,430		108,210		74,066		97,602
Depreciation, accretion, and amortization		(158,554)		(160,111)		(159,723)		(159,801)
Loss from extinguishment of debt, net		(18,189)		(34,512)		—		—
Net income (loss)		5,256		(15,370)		32,711		53,641
Net income per common share - basic	$	0.04	$	(0.12)	$	0.26	$	0.43
Net income per common share - diluted		0.04		(0.12)		0.26		0.43

(1) The sums of quarterly earnings per share data may not equal annual data due to rounding.