CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income	$ 66,341	$ 23,273	$ 100,039	$ 64,525
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,441	56,826	116,009	113,887
Equity-based compensation	4,700	2,344	10,468	7,097
Impairment charges		308		308
Deferred income taxes	(280)	10,812	(4,371)	21,747
(Gain) loss on disposal of property, plant and equipment	3,456	588	6,097	(795)
Changes in certain assets and liabilities:
Accounts receivable	(99,696)	(19,826)	(188,646)	(130,764)
Inventories	11,230	1,660	(6,124)	34,008
Other assets	345	6,783	7,704	10,141
Accounts payable	13,385	(46,370)	18,426	(7,382)
Income taxes receivable/payable	(4,964)	(23,304)	14,429	(26,326)
Accrued expenses and liabilities	23,056	19,621	(25,264)	(24,021)
Net cash provided by (used in) operating activities	76,014	32,715	48,767	62,425
Investing activities:
Purchases of property, plant and equipment	(33,534)	(49,236)	(58,375)	(94,582)
Proceeds from maturities of short-term commercial paper				31,520
Other investing activities	2,314	863	31,198	3,277
Net cash provided by used in investing activities	(31,220)	(48,373)	(27,177)	(59,785)
Financing activities:
Issuance of current and long-term debt	63,945	32	107,398	409,293
Repayment of current and long-term debt	(76,412)	(202,312)	(132,658)	(508,003)
Debt issuance costs		(195)		(6,192)
Proceeds from exercise of stock options, including related tax effect	8,516	2,977	11,421	10,591
Contributions from noncontrolling investors, net	(606)	5,286	4,764	5,697
Dividends paid	(25,666)	(24,238)	(50,181)	(46,190)
Net cash used in financing activities	(30,223)	(218,450)	(59,256)	(134,804)
Increase (decrease) in cash and equivalents	14,571	(234,108)	(37,666)	(132,164)
Cash and equivalents at beginning of period	342,919	477,861	395,156	375,917
Cash and equivalents at end of period	357,490	243,753	357,490	243,753
Supplemental disclosure information:
Cash paid for interest	20,838	17,583	60,501	67,315
Cash paid for federal and state income taxes, net	$ 43,008	$ 27,360	$ 45,151	$ 38,525