CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 297,366	$ 306,997
Accounts receivable, net of allowances aggregating $27,144 and $29,249, respectively	480,044	496,226
Unbilled accounts receivable	28,106	36,190
Deferred costs	19,037	18,914
Inventories and supplies	182,038	178,428
Prepaid expenses and other current assets	55,180	56,116
Total current assets	1,061,771	1,092,871
Property, plant and equipment, net	1,609,490	1,611,827
Other assets:
Goodwill	469,860	465,154
Permits and other intangibles, net	490,952	498,721
Other	13,580	13,347
Total other assets	974,392	977,222
Total assets	3,645,653	3,681,920
Current liabilities:
Accounts payable	218,676	229,534
Deferred revenue	64,379	64,397
Accrued expenses	183,957	190,721
Current portion of closure, post-closure and remedial liabilities	21,569	20,016
Total current liabilities	488,581	504,668
Other liabilities:
Closure and post-closure liabilities, less current portion of $6,019 and $6,220, respectively	54,332	52,111
Remedial liabilities, less current portion of $15,550 and $13,796, respectively	111,057	114,211
Long-term obligations	1,633,968	1,633,272
Deferred taxes, unrecognized tax benefits and other long-term liabilities	294,085	293,417
Total other liabilities	2,093,442	2,093,011
Commitments and contingent liabilities (See Note 15)
Stockholders’ equity:
Common Stock, $.01 par value: Authorized 80,000,000; shares issued and outstanding 57,188,805 and 57,297,978 shares, respectively	572	573
Shares held under employee participation plan	0	(469)
Additional paid-in capital	720,383	725,670
Accumulated other comprehensive loss	(208,275)	(214,326)
Accumulated earnings	550,950	572,793
Total stockholders’ equity	1,063,630	1,084,241
Total liabilities and stockholders’ equity	$ 3,645,653	$ 3,681,920