Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 22,055	$ 68,221
Restricted cash	1,683	2,088
Accounts receivable, net of allowance for doubtful accounts of $5,634 and $5,647, respectively	216,077	206,868
Related party receivables and prepaid expenses	702	711
Inventories, net	14,845	14,314
Prepaid expenses and other current assets	33,429	31,091
Total current assets	288,791	323,293
Property, plant and equipment, net of accumulated depreciation of $192,177 and $193,760, respectively	81,862	87,851
Operating lease right-of-use assets, net	66,743	68,861
Goodwill	359,309	359,781
Intangible assets, net	280,891	292,664
Deferred income tax assets	6,370	6,606
Other noncurrent assets	20,756	18,723
Total assets	1,104,722	1,157,779
Current liabilities
Accounts payable	73,666	76,027
Related party payables	124	97
Income tax payable	1,531	2,466
Accrued liabilities	122,080	126,399
Accrued compensation and benefits	62,392	63,467
Accrued interest	24,059	48,769
Customer deposits	17,648	21,277
Deferred revenue	21,182	16,377
Obligation for claim payment	28,222	29,328
Current portion of finance lease liabilities	11,143	12,231
Current portion of operating lease liabilities	17,852	18,349
Current portion of long-term debts	39,713	39,952
Total current liabilities	419,612	454,739
Long-term debt, net of current maturities	1,499,031	1,498,004
Finance lease liabilities, net of current portion	11,401	13,287
Pension liabilities, net	35,335	35,515
Deferred income tax liabilities	9,154	9,569
Long-term income tax liabilities	2,260	2,759
Operating lease liabilities, net of current portion	54,929	56,814
Other long-term liabilities	13,336	13,624
Total liabilities	2,045,058	2,084,311
Commitments and Contingencies (Note 8)
Stockholders' equity (deficit)
Common stock, par value of $0.0001 per share; 1,600,000,000 shares authorized; 61,643,718 shares issued and 59,192,012 shares outstanding at March 31, 2021 and 51,693,931 shares issued and 49,242,225 shares outstanding at December 31, 2020	16	15
Preferred stock, par value of $0.0001 per share; 20,000,000 shares authorized; 2,779,369 shares issued and outstanding at March 31, 2021 and 3,290,050 shares issued and outstanding at December, 2020	1	1
Additional paid in capital	471,804	446,739
Less: Common Stock held in treasury, at cost; 2,451,706 shares at March 31, 2021 and December 31, 2020	(10,949)	(10,949)
Equity-based compensation	52,570	52,183
Accumulated deficit	(1,429,238)	(1,390,038)
Accumulated other comprehensive loss:
Foreign currency translation adjustment	(7,319)	(7,419)
Unrealized pension actuarial losses, net of tax	(17,221)	(17,064)
Total accumulated other comprehensive loss	(24,540)	(24,483)
Total stockholders' deficit	(940,336)	(926,532)
Total liabilities and stockholders' deficit	$ 1,104,722	$ 1,157,779