Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Activities
Net income	$ 9,822	$ 7,140
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	2,808	3,191
Amortization of bond premiums	216	127
Provision for losses on accounts receivable, net of adjustments	(130)	269
Provision for excess and obsolete inventories, net	4	169
Share-based compensation	412	392
Excess tax benefits from stock options exercised and restricted stock awards vested	(356)	(109)
(Gain) loss on disposal of assets	(24)	7
Foreign currency transaction gain	31	19
Interest income on note receivable	(10)	(10)
Deferred income taxes	(1,154)	(1,205)
Changes in assets and liabilities:
Accounts receivable	(6,511)	5,046
Income tax receivable	1,429	(172)
Inventories	(2,755)	(1,541)
Prepaid expenses and other	(397)	(99)
Accounts payable	3,441	(1,838)
Deferred revenue	204	0
Accrued liabilities	2,039	(2,895)
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	9,069	8,491
Investing Activities
Capital expenditures	(3,616)	(997)
Proceeds from sale of property, plant and equipment	27	0
Investment in certificates of deposits	0	(238)
Maturities of certificates of deposits	1,403	720
Purchase of investments held to maturity	0	(1,396)
Maturities of investments	2,717	610
Proceeds from called investment	253	0
Principal payments from note receivable	17	20
Net cash provided by (used in) investing activities	801	(1,281)
Financing Activities
Borrowings under revolving credit facility	0	1,955
Payments under revolving credit facility	0	(1,955)
Stock options exercised	340	354
Excess tax benefits from stock options exercised and restricted stock awards vested	356	109
Repurchase of stock	(2,981)	(1,115)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations	(2,285)	(652)
Net increase in cash and cash equivalents	7,585	6,558
Cash and cash equivalents, beginning of period	12,085	3,159
Cash and cash equivalents, end of period	$ 19,670	$ 9,717