Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash, cash equivalents and restricted cash	$ 69,496	$ 39,719
Accounts receivable, net of allowance of $742 in 2021 and $997 in 2020	205,399	153,511
Inventory	49,204	40,410
Prepaid supplies and other	28,742	39,096
TOTAL CURRENT ASSETS	352,841	272,736
Property and equipment, net	2,129,934	1,939,776
Lease incentive	102,913	126,007
Other assets	113,878
Goodwill and acquired intangibles	505,125	516,290
Operating lease assets	62,644	68,824
Intangibles	109,151	120,316
Goodwill	395,974	395,974
TOTAL ASSETS	3,267,335	3,001,745
CURRENT LIABILITIES:
Accounts payable	174,237	141,425
Accrued salaries, wages and benefits	56,652	56,506
Accrued expenses	14,950	19,005
Current portion of debt obligations	628	13,746
Current portion of lease obligations	18,783	17,784
Unearned revenue and grants	47,381	53,522
TOTAL CURRENT LIABILITIES	312,631	301,988
Long term debt	1,298,735	1,465,331
Post-retirement obligations	21,337	35,099
Long term lease obligations	44,387	51,128
Other liabilities	49,662	47,963
Stock Warrants	915	103,474
Deferred income taxes	217,291	141,265
TOTAL LIABILITIES	1,944,958	2,146,248
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; 150,000,000 shares authorized; 74,142,183 and 59,560,036 shares issued and outstanding in 2021 and 2020, respectively	741	596
Additional paid-in capital	1,074,286	855,547
Retained earnings	309,430	78,010
Accumulated other comprehensive loss	(62,080)	(78,656)
TOTAL STOCKHOLDERS’ EQUITY	1,322,377	855,497
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 3,267,335	$ 3,001,745