Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities:
Net income (loss)	$ 52,207	$ (47,777)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Non-cash operating items (Note 2)	(60,222)	40,900
Changes in operating assets and liabilities:
Other current assets	(422)	56
Accrued employment costs and other current liabilities	113	(570)
Income taxes receivable and payable	9	(898)
Pension and other postretirement liabilities	(581)	(948)
Other liabilities	496	1,926
Net cash (used in) provided by operating activities	(8,400)	(7,311)
Financing activities:
Dividend paid	0	(170,130)
Net cash (used in) provided by financing activities	0	(170,130)
Cash, cash equivalents and restricted cash - period (decrease) increase	(8,400)	(177,441)
Cash, cash equivalents and restricted cash - beginning of year	31,935	259,371
Cash, cash equivalents and restricted cash - end of period	$ 23,535	$ 81,930