CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 257,857	$ 184,708
Accounts receivable, net of allowances aggregating $28,782 and $31,426, respectively	512,376	496,004
Unbilled accounts receivable	41,542	25,940
Deferred costs	19,970	18,758
Inventories and supplies	177,288	149,521
Prepaid expenses and other current assets	40,898	46,265
Total current assets	1,049,931	921,196
Property, plant and equipment, net	1,648,571	1,532,467
Other assets:
Deferred financing costs	1,197	1,847
Goodwill	470,633	453,105
Permits and other intangibles, net	507,337	506,818
Other	34,944	15,995
Total other assets	1,014,111	977,765
Total assets	3,712,613	3,431,428
Current liabilities:
Accounts payable	226,776	241,183
Deferred revenue	66,023	61,882
Accrued expenses	226,080	193,660
Current portion of closure, post-closure and remedial liabilities	20,217	20,395
Total current liabilities	539,096	517,120
Other liabilities:
Closure and post-closure liabilities, less current portion of $6,057 and $7,229, respectively	56,510	49,020
Remedial liabilities, less current portion of $14,160 and $13,166, respectively	114,921	118,826
Long-term obligations	1,632,577	1,382,543
Deferred taxes, unrecognized tax benefits and other long-term liabilities	268,564	267,637
Total other liabilities	2,072,572	1,818,026
Commitments and contingent liabilities
Stockholders’ equity:
Common Stock, $.01 par value: Authorized 80,000,000; shares issued and outstanding 57,389,531 and 57,593,201 shares, respectively	574	576
Shares held under employee participation plan	(469)	(469)
Additional paid-in capital	726,878	738,401
Accumulated other comprehensive loss	(211,544)	(254,892)
Accumulated earnings	585,506	612,666
Total stockholders’ equity	1,100,945	1,096,282
Total liabilities and stockholders’ equity	$ 3,712,613	$ 3,431,428