Impairment of Assets Held for Sale (Valuation Allowance against Assets and Liabilities Held for Sale) (Details) - Renewable Power Systems [Member] $ in Thousands	Dec. 31, 2019 USD ($)
Assets:
Accounts receivable	$ 18,140
Inventories	17,929
Other current assets	363
Other assets	142
Total assets	36,574
Valuation, allowance	(14,438)
Total assets, net	22,136
Liabilities:
Accounts payable	1,962
Accrued liabilities	7,733
Other liabilities	491
Total liabilities	$ 10,186