CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 38,934	$ 43,772
Restricted cash and cash equivalents	9,435	13,169
Accounts receivable – trade, net	126,841	142,201
Accounts receivable – other	52,137	23,263
Contracts in progress	73,882	91,579
Inventories	66,966	63,103
Other current assets	20,554	27,044
Current assets held for sale	4,816	8,089
Total current assets	393,565	412,220
Net property, plant and equipment, and finance lease	88,645	97,053
Goodwill	47,136	47,160
Intangible assets	23,691	25,300
Right-of-use assets	10,272	12,498
Other assets	34,902	24,966
Non-current assets held for sale	7,543	7,322
Total assets	605,754	626,519
Revolving credit facilities	0	179,000
Last out term loans	0	103,953
Financing lease liabilities	852	(38)
Accounts payable	79,983	109,913
Accrued employee benefits	17,365	18,256
Advance billings on contracts	54,046	75,287
Accrued warranty expense	26,803	33,376
Operating lease liabilities	3,968	4,323
Other accrued liabilities	86,772	68,848
Current liabilities held for sale	6,925	9,538
Total current liabilities	276,714	602,494
Revolving credit facilities	181,900	0
Last out term loans	173,330	0
Pension and other accumulated postretirement benefit liabilities	236,372	259,272
Non-current finance lease liabilities	29,917	30,454
Non-current operating lease liabilities	6,381	8,388
Other non-current liabilities	21,918	20,850
Total liabilities	926,532	921,458
Commitments and contingencies
Stockholders' deficit:
Common stock, par value $0.01 per share, authorized shares of 500,000; issued and outstanding shares of 52,006 and 46,374 at September 30, 2020 and December 31, 2019, respectively	4,760	4,699
Capital in excess of par value	1,157,811	1,142,614
Treasury stock at cost, 716 and 616 shares at September 30, 2020 and December 31, 2019, respectively	(105,985)	(105,707)
Accumulated deficit	(1,354,794)	(1,339,888)
Accumulated other comprehensive income (loss)	(23,443)	1,926
Stockholders' deficit attributable to shareholders	(321,651)	(296,356)
Non-controlling interest	873	1,417
Total stockholders' deficit	(320,778)	(294,939)
Total liabilities and stockholders' deficit	$ 605,754	$ 626,519