CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating Activities:
Net income	$ 10,210	$ 7,382
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	7,316	7,381
Amortization of deferred financing costs	23	23
Deferred income taxes	165	689
Gain on sale of property, plant and equipment	(11)	(8)
Stock-based compensation	524	460
Changes in operating assets and liabilities:
Trade receivables, net	(3,640)	(3,172)
Inventories	2,149	(50)
Prepaid expenses and other current assets	446	(371)
Other assets	1	(13)
Accounts payable and accrued expenses	(1,445)	167
Other liabilities	200	12
Net cash provided by operating activities	15,938	12,500
Investing Activities:
Purchase of property, plant and equipment	(5,547)	(4,012)
Proceeds from sale of property, plant and equipment	211	51
Net cash used in investing activities	(5,336)	(3,961)
Financing Activities:
Repayment of term loans	(2,500)	(1,250)
Cash dividends paid	(1,394)
Purchase of treasury shares	(168)	(212)
Net cash used in financing activities	(4,062)	(1,453)
Proceeds from exercise of stock options		9
Net increase in cash and cash equivalents	6,540	7,086
Cash and cash equivalents at beginning of period	49,475	29,787
Cash and cash equivalents at end of period	$ 56,015	$ 36,873