CONSOLIDATED BALANCE SHEETS (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 377,576	$ 302,210
Marketable securities	128	3,174
Accounts receivable, net of allowances aggregating $15,729 and $23,704, respectively	352,809	332,678
Unbilled accounts receivable	30,588	19,117
Deferred costs	6,289	6,891
Prepaid expenses and other current assets	32,828	28,939
Supplies inventories	47,270	44,546
Deferred tax assets	18,884	14,982
Total current assets	866,372	752,537
Property, plant and equipment:
Land	32,782	31,654
Asset retirement costs (non-landfill)	2,371	2,242
Landfill assets	52,514	54,519
Buildings and improvements	158,705	147,285
Camp equipment	99,611	62,717
Vehicles	206,388	162,397
Equipment	675,494	537,937
Furniture and fixtures	3,700	2,293
Construction in progress	43,150	33,005
Property, plant and equipment, gross	1,274,715	1,034,049
Less-accumulated depreciation and amortization	426,439	378,655
Total property, plant and equipment, net	848,276	655,394
Other assets:
Long-term investments	5,311	5,437
Deferred financing costs	15,061	7,768
Goodwill	88,511	60,252
Permits and other intangibles, net of accumulated amortization of $67,035 and $60,633, respectively	127,068	114,400
Other	14,481	6,687
Total other assets	250,432	194,544
Total assets	1,965,080	1,602,475
Current liabilities:
Current portion of capital lease obligations	6,520	7,954
Accounts payable	156,106	136,978
Deferred revenue	28,462	30,745
Accrued expenses	118,716	116,089
Current portion of closure, post-closure and remedial liabilities	15,626	14,518
Total current liabilities	325,430	306,284
Other liabilities:
Closure and post-closure liabilities, less current portion of $6,313 and $5,849, respectively	28,595	32,830
Remedial liabilities, less current portion of $9,313 and $8,669, respectively	127,859	128,944
Long-term obligations	524,994	264,007
Capital lease obligations, less current portion	9,109	6,839
Unrecognized tax benefits and other long-term liabilities	91,725	82,744
Total other liabilities	782,282	515,364
Common stock, $.01 par value:
Authorized 80,000,000; shares issued and outstanding 52,986,122 and 52,772,392 shares, respectively	530	528
Treasury stock	(4,274)	(2,467)
Shares held under employee participation plan	(777)	(777)
Additional paid-in capital	495,237	488,384
Accumulated other comprehensive income	70,366	50,759
Accumulated earnings	296,286	244,400
Total stockholders' equity	857,368	780,827
Total liabilities and stockholders' equity	$ 1,965,080	$ 1,602,475