UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 68,765	$ 67,800
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	196,904	116,794
Pre-tax, non-cash acquisition accounting adjustments	13,559	0
Allowance for doubtful accounts	5,281	809
Amortization of deferred financing costs and debt discount	2,539	1,173
Accretion of environmental liabilities	8,628	7,409
Changes in environmental liability estimates	(2,417)	(3,553)
Deferred income taxes	272	(494)
Stock-based compensation	6,389	5,235
Excess tax benefit of stock-based compensation	(1,589)	(1,786)
Income tax benefit related to stock option exercises	1,579	1,776
Other expense (income)	(2,030)	465
Write-off of deferred financing costs and debt premium	0	5,341
Environmental expenditures	(15,928)	(7,833)
Changes in assets and liabilities, net of acquisitions
Accounts receivable	(72,377)	59,881
Inventories and supplies	1,710	(7,692)
Other current assets	11,860	12,822
Accounts payable	37,257	(18,969)
Other current and long-term liabilities	19,712	(6,486)
Net cash from operating activities	280,114	232,692
Cash flows from investing activities:
Additions to property, plant and equipment	(207,641)	(130,326)
Proceeds from sales of fixed assets	3,700	4,190
Acquisitions, net of cash acquired	(59,458)	(92,475)
Additions to intangible assets, including costs to obtain or renew permits	(4,357)	(2,409)
Purchase of marketable securities	0	(10,517)
Other	(11)	5,120
Net cash used in investing activities	(267,767)	(226,417)
Cash flows from financing activities:
Change in uncashed checks	9,754	(13,955)
Proceeds from exercise of stock options	399	231
Remittance of shares, net	(599)	(1,604)
Proceeds from employee stock purchase plan	5,327	4,627
Deferred financing costs paid	(2,446)	(9,638)
Payments on capital leases	(4,096)	(5,303)
Principal payment on debt	0	(520,000)
Issuance of senior unsecured notes, including premium	0	800,000
Issuance costs related to 2012 issuance of common stock	(250)	0
Distribution of cash earned on employee participation plan	0	(55)
Excess tax benefit of stock-based compensation	1,589	1,786
Net cash from financing activities	9,678	256,089
Effect of exchange rate change on cash	(3,226)	527
Increase in cash and cash equivalents	18,799	262,891
Cash and cash equivalents, beginning of period	229,836	260,723
Cash and cash equivalents, end of period	248,635	523,614
Cash payments for interest and income taxes:
Interest paid	58,084	41,176
Income taxes paid	8,386	5,578
Non-cash investing and financing activities:
Property, plant and equipment accrued	39,804	31,978
Transfer of inventory to property, plant and equipment	$ 11,369	$ 0