CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 249,007	$ 310,073
Marketable securities	213	12,435
Accounts receivable, net of allowances aggregating $20,094 and $18,106, respectively	566,394	579,394
Unbilled accounts receivable	40,832	26,568
Deferred costs	16,523	16,134
Inventories and supplies	152,443	152,096
Prepaid expenses and other current assets	56,677	41,962
Deferred tax assets	32,469	32,517
Total current assets	1,114,558	1,171,179
Property, plant and equipment, net	1,588,286	1,602,170
Other assets:
Deferred financing costs	20,036	20,860
Goodwill	565,062	570,960
Permits and other intangibles, net	557,211	569,973
Other	18,802	18,536
Total other assets	1,161,111	1,180,329
Total assets	3,863,955	3,953,678
Current liabilities:
Current portion of capital lease obligations	1,119	1,329
Accounts payable	284,768	316,462
Deferred revenue	56,469	55,454
Accrued expenses	213,096	236,829
Current portion of closure, post-closure and remedial liabilities	31,866	29,471
Total current liabilities	587,318	639,545
Other liabilities:
Closure and post-closure liabilities, less current portion of $7,629 and $5,884, respectively	40,809	41,201
Remedial liabilities, less current portion of $24,237 and $23,587, respectively	144,485	148,911
Long-term obligations	1,400,000	1,400,000
Capital lease obligations, less current portion	913	1,435
Deferred taxes, unrecognized tax benefits and other long-term liabilities	244,795	246,947
Total other liabilities	1,831,002	1,838,494
Common stock, $.01 par value:
Authorized 80,000,000; shares issued and outstanding 60,717,774 and 60,672,180 shares, respectively	607	607
Shares held under employee participation plan	(469)	(469)
Additional paid-in capital	900,726	898,165
Accumulated other comprehensive loss	(61,081)	(19,556)
Accumulated earnings	605,852	596,892
Total stockholders’ equity	1,445,635	1,475,639
Total liabilities and stockholders’ equity	$ 3,863,955	$ 3,953,678