UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 10,502	$ 32,015
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	60,006	36,831
Pre-tax, non-cash acquisition accounting adjustments	13,559	0
Allowance for doubtful accounts	1,823	203
Amortization of deferred financing costs and debt discount	846	367
Accretion of environmental liabilities	2,835	2,416
Changes in environmental liability estimates	(58)	(646)
Deferred income taxes	32	(269)
Stock-based compensation	1,887	2,141
Excess tax benefit of stock-based compensation	(1,227)	(713)
Income tax benefit related to stock option exercises	1,216	713
Other expense (income)	(525)	299
Environmental expenditures	(5,291)	(1,722)
Changes in assets and liabilities, net of acquisitions
Accounts receivable	(28,726)	(11,502)
Inventories and supplies	13,573	(1,453)
Other current assets	6,377	(1,890)
Accounts payable	(16,112)	(4,302)
Other current and long-term liabilities	(21,128)	(22,935)
Net cash from operating activities	39,589	29,553
Cash flows from investing activities:
Additions to property, plant and equipment	(72,249)	(27,661)
Proceeds from sales of fixed assets	921	425
Acquisitions, net of cash acquired	(197)	(8,751)
Additions to intangible assets, including costs to obtain or renew permits	(725)	(425)
Purchase of marketable securities	0	(4,468)
Other	0	5,120
Net cash used in investing activities	(72,250)	(35,760)
Cash flows from financing activities:
Change in uncashed checks	26,419	(13,576)
Proceeds from exercise of stock options	397	30
Remittance of shares, net	(41)	0
Proceeds from employee stock purchase plan	1,546	1,238
Deferred financing costs paid	(2,318)	0
Payments on capital leases	(1,346)	(2,166)
Issuance costs related to 2012 issuance of common stock	(250)	0
Distribution of cash earned on employee participation plan	0	(38)
Excess tax benefit of stock-based compensation	1,227	713
Net cash from financing activities	25,634	(13,799)
Effect of exchange rate change on cash	(705)	810
Decrease in cash and cash equivalents	(7,732)	(19,196)
Cash and cash equivalents, beginning of period	229,836	260,723
Cash and cash equivalents, end of period	222,104	241,527
Cash payments for interest and income taxes:
Interest paid	21,725	20,811
Income taxes paid	3,662	1,050
Non-cash investing and financing activities:
Property, plant and equipment accrued	21,722	19,766
Transfer of inventory to property, plant and equipment	$ 11,369	$ 0