Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income (loss)	$ 29,607	$ 21,984	$ (38,118)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	19,276	23,680	28,070
Amortization of deferred financing fees	596	1,089	229
Deferred income taxes	12,697	(6,942)	(41,347)
Centennial asset impairment charge	17,443	0	105,119
Loss (gain) on sale of assets	146	(1,811)	(7,339)
Other	1,649	1,754	14,667
Working capital changes, excluding the effect of business acquisitions:
Accounts receivable	(10,417)	66,486	(22,506)
Inventories	4,902	24,149	(879)
Other current assets	(2,632)	4,530	201
Accounts payable	27,098	(28,867)	(2,963)
Other current liabilities	(6,430)	1,950	(15,335)
Net cash provided by operating activities	93,935	108,002	19,799
Investing Activities
Expenditures for property, plant and equipment	(16,167)	(10,615)	(57,500)
Acquisition of business	0	(413)	(25,000)
Proceeds from the sale of assets	8,060	3,471	8,134
Other	(1,710)	(734)	(568)
Net cash used for investing activities	(9,817)	(8,291)	(74,934)
Financing Activities
Reductions of long-term debt	(46,564)	(6,282)	(9,399)
Net additions (reductions) to revolving credit agreements	4,349	(71,635)	73,546
Cash dividends paid	(7,262)	(7,296)	(7,755)
Purchase of treasury shares	(6,044)	(24,010)	(35,075)
Financing fees paid	(186)	0	(333)
Other	(3)	922	(5)
Net cash provided by (used for) financing activities	(55,710)	(108,301)	20,979
Effect of exchange rate changes on cash	(259)	(46)	(99)
Cash and Cash Equivalents
Increase (decrease) for the year	28,149	(8,636)	(34,255)
Balance at the beginning of the year	52,499	61,135	95,390
Balance at the end of the year	$ 80,648	$ 52,499	$ 61,135