Statements of Consolidated Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash and Cash Equivalents, at Beginning of Period	$ 432,759	$ 484,502
Net income	65,827	66,560
Depreciation, Amortization and Accretion, Net	119,686	120,223
Non-cash compensation and employee benefits	13,474	12,182
Increase in deferred income taxes	5,160	18,708
Provision for uncollectible accounts	(33)	1,402
Loss (gain) from sale of property and equipment	(1,348)	(5,375)
Receivables	(20,350)	(119,659)
Prepaid expense	(2,380)	(2,946)
Accounts payable	34,714	34,658
Accrued variable compensation	(28,452)	(6,307)
Accrued liabilities, excluding accrued variable compensation and employee benefits	32,315	32,962
Self-insurance accruals	(7,764)	5,617
Accrued income taxes	2,636	3,164
Employee benefits	(26,476)	(39,132)
Other	(11,255)	(412)
Net Cash Provided by (Used in) Operating Activities	175,754	121,645
Capital expenditures	(116,489)	(123,366)
Software expenditures	(7,865)	(5,613)
Proceeds from sales of property and equipment	12,223	22,391
Net cash used in investing activities	(112,131)	(106,588)
Payment of capital leases	(13,032)	(6,141)
Net proceeds from short-term borrowings	326	801
Proceeds from exercise of stock options	559	13,573
Excess tax benefit from share-based compensation	2,913	2,413
Payments of common dividends	(17,264)	(11,413)
Repurchases of common stock	(34,804)	0
Net Cash Used in Financing Activities	(61,302)	(767)
Decrease in Cash and Cash Equivalents	2,321	14,290
Cash and Cash Equivalents, at End of Period	435,080	498,792
Cash paid (refunded) for income taxes, net	30,042	19,169
Cash paid for interest	25,984	26,232
Capital Expenditures Incurred but Not yet Paid	4,536	0
Repurchases of common stock included in current liabilities	1,550	0
Property, plant and equipment acquired through partial non-monetary exchanges	10,947	936
Capital Lease Obligations Incurred	$ 116	$ 7,233