CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 129,674	$ 127,252	$ 130,515
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	161,646	122,663	92,473
Allowance for doubtful accounts	1,213	759	1,043
Amortization of deferred financing costs and debt discount	1,793	1,572	2,921
Accretion of environmental liabilities	9,917	9,680	10,307
Changes in environmental liability estimates	(8,458)	(2,840)	(8,328)
Deferred income taxes	34,163	37,836	4,919
Other (expense) income	802	(3,048)	(2,795)
Stock-based compensation	7,494	8,164	7,219
Excess tax benefit of stock-based compensation	(2,556)	(3,352)	(1,751)
Income tax benefit related to stock option exercises	2,546	3,347	1,739
Gains on sale of businesses	0	0	(2,678)
Write-off of deferred financing costs and debt (premium) discount	5,341	0	1,394
Environmental expenditures	(11,191)	(11,319)	(10,236)
Changes in assets and liabilities:
Accounts receivable	54,373	(65,210)	(49,411)
Inventories and supplies	(12,871)	(11,696)	(3,129)
Other current assets	9,334	(25,065)	(7,421)
Accounts payable	5,930	(8,116)	38,553
Other current and long-term liabilities	(64,785)	(1,096)	18,774
Net cash from operating activities	324,365	179,531	224,108
Cash flows from investing activities:
Additions to property, plant and equipment	(197,397)	(148,513)	(116,450)
Proceeds from sales of fixed assets and assets held for sale	8,125	6,794	16,053
Acquisitions, net of cash acquired	(1,373,921)	(336,960)	(14,646)
Additions to intangible assets including costs to obtain or renew permits	(4,046)	(2,927)	(4,204)
Purchase of marketable securities	(10,517)	0	(2,127)
Purchase of investment securities	0	0	(10,506)
Proceeds from sales of marketable securities	0	425	3,557
Proceeds from insurance settlement	0	0	1,336
Proceeds from sale of long-term investments	0	1,000	1,300
Other	5,120	0	0
Net cash used in investing activities	(1,572,636)	(480,181)	(125,687)
Cash flows from financing activities:
Change in uncashed checks	(12,070)	9,822	(1,266)
Proceeds from exercise of stock options	288	1,350	862
Remittance of shares, net	(2,912)	(4,061)	(399)
Excess tax benefit of stock-based compensation	2,556	3,352	1,751
Deferred financing costs paid	(19,056)	(8,463)	(353)
Proceeds from employee stock purchase plan	6,196	3,516	2,449
Payments on capital leases	(6,599)	(7,837)	(5,126)
Proceeds from issuance of common stock, net	369,520	0	0
Principal payments on debt	(520,000)	0	(30,000)
Distribution of cash earned on employee participation plan	(55)	(189)	(148)
Issuance of senior unsecured notes, at par	1,400,000	0	0
Issuance of senior secured notes, including premium	0	261,250	0
Net cash from financing activities	1,217,868	258,740	(32,230)
Effect of exchange rate change on cash	(484)	423	2,473
(Decrease) increase in cash and cash equivalents	(30,887)	(41,487)	68,664
Cash and cash equivalents, beginning of year	260,723	302,210	233,546
Cash and cash equivalents, end of period	229,836	260,723	302,210
Cash payments for interest and income taxes:
Interest paid	41,817	31,201	26,985
Income taxes paid	13,179	48,725	56,015
Non-cash investing and financing activities:
Property, plant and equipment accrued	29,788	18,682	7,844
Accrued working capital adjustments	(750)	3,694	0
Assets acquired through capital lease	154	1,807	10,130
Issuance of acquisition-related common stock, net	$ 0	$ 0	$ 1,015