CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
OPERATING ACTIVITIES:
Net income	$ 7,753	$ 4,924
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	7,984	7,885
Amortization of deferred financing costs	6	23
Deferred income taxes	96	(228)
Loss (gain) on sale of property, plant and equipment	31	(111)
Stock-based compensation	485	575
Changes in operating assets and liabilities:
Trade receivables, net	(1,516)	717
Inventories, net	1,238	(201)
Prepaid expenses and other current assets	549	1,197
Other assets	3	(18)
Accounts payable and accrued expenses	(1,612)	(1,616)
Other liabilities	(100)	630
Net cash provided by operating activities	14,917	13,777
INVESTING ACTIVITIES:
Purchase of property, plant and equipment	(7,900)	(6,310)
Proceeds from sale of property, plant and equipment	70	199
Net cash used in investing activities	(7,830)	(6,111)
FINANCING ACTIVITIES:
Repayment of term loans		(16,667)
Cash dividends paid	(1,391)	(1,399)
Proceeds from exercise of stock options	154
Purchase of treasury shares	(2,818)	(158)
Net cash used in financing activities	(4,055)	(18,224)
Net increase (decrease) in cash and cash equivalents	3,032	(10,558)
Cash and cash equivalents at beginning of period	59,926	58,332
Cash and cash equivalents at end of period	$ 62,958	$ 47,774