UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 3,306	$ 37,632
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	136,129	135,431
Goodwill impairment charge	31,992	0
Allowance for doubtful accounts	4,536	4,605
Amortization of deferred financing costs and debt discount	1,639	1,576
Accretion of environmental liabilities	5,218	5,333
Changes in environmental liability estimates	887	(1,429)
Deferred income taxes	(908)	(1)
Stock-based compensation	6,146	4,340
Excess tax benefit of stock-based compensation	(102)	(644)
Deferred Tax Expense from Stock Options Exercised	(72)	644
Net tax (deficiency) benefit on stock based awards	(1,100)	(1,000)
Other expense (income)	251	(3,523)
Environmental expenditures	(11,532)	(7,443)
Changes in assets and liabilities, net of acquisitions
Accounts receivable and unbilled accounts receivable	(133,031)	(9,542)
Inventories and supplies	17,694	(9,556)
Other current assets	(816)	(8,721)
Accounts payable	108,639	(46,421)
Other current and long-term liabilities	23,839	12,663
Net cash from operating activities	193,815	114,944
Cash flows from investing activities:
Additions to property, plant and equipment	(124,145)	(138,186)
Proceeds from sales of fixed assets	2,646	2,986
Proceeds from sales of marketable securities	0	12,947
Acquisitions, net of cash acquired	(79,610)	(6,150)
Additions to intangible assets, including costs to obtain or renew permits	(3,088)	(2,891)
Net cash used in investing activities	(204,197)	(131,294)
Cash flows from financing activities:
Change in uncashed checks	(22,160)	3,162
Proceeds from exercise of stock options	397	0
Issuance of restricted shares, net of shares remitted	(1,837)	(2,215)
Repurchases of common stock	(32,203)	(14,657)
Proceeds from employee stock purchase plan	0	4,364
Repayment of long-term obligations	0	5,000
Payments on capital leases	(471)	(1,190)
Excess tax benefit of stock-based compensation	102	644
Net cash from financing activities	(56,172)	(14,892)
Effect of exchange rate change on cash	(6,704)	(187)
Decrease in cash and cash equivalents	(73,258)	(31,429)
Cash and cash equivalents, beginning of period	246,879	310,073
Cash and cash equivalents, end of period	173,621	278,644
Cash payments for interest and income taxes:
Interest paid	37,411	37,070
Income taxes (received) paid	3,068	14,304
Non-cash investing and financing activities:
Accrual for repurchased shares	0	1,562
Property, plant and equipment accrued	34,799	21,934
Receivable for estimated purchase price adjustment	$ 2,518	$ 0