Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 43,462	$ 32,699
Accounts receivable, net of allowance of $1,014 in 2018 and $2,445 in 2017	93,662	109,114
Inventory	24,412	22,169
Prepaid supplies and other	15,698	20,521
TOTAL CURRENT ASSETS	177,234	184,503
Property and equipment, net	1,226,500	1,159,962
Lease incentive	68,006	80,684
Other assets	37,618	25,435
Goodwill and acquired intangibles	43,710	44,577
Convertible note hedges	0	53,683
Intangibles	6,431	7,298
Goodwill	37,279	37,279
TOTAL ASSETS	1,553,068	1,548,844
CURRENT LIABILITIES:
Accounts payable	101,205	99,728
Accrued salaries, wages and benefits	31,416	40,127
Accrued expenses	11,387	10,455
Current portion of debt obligations	14,860	18,512
Unearned revenue	15,204	15,850
TOTAL CURRENT LIABILITIES	174,072	184,672
Long term debt	527,226	497,246
Convertible note obligations	0	54,359
Post-retirement obligations	29,355	61,355
Other liabilities	46,334	45,353
Stock Warrants	186,093	211,136
Deferred income taxes	119,289	99,444
TOTAL LIABILITIES	1,082,369	1,153,565
Commitments and contingencies (Note H)
STOCKHOLDERS’ EQUITY:
Preferred stock, 20,000,000 shares authorized, including 75,000 Series A Junior Participating Preferred Stock	0	0
Common stock, par value $0.01 per share; 110,000,000 shares authorized; 59,080,387 and 59,057,195 shares issued and outstanding in 2018 and 2017, respectively	591	591
Additional paid-in capital	470,676	471,456
Retained earnings (accumulated deficit)	60,381	(13,748)
Accumulated other comprehensive loss	(60,949)	(63,020)
TOTAL STOCKHOLDERS’ EQUITY	470,699	395,279
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 1,553,068	$ 1,548,844