Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating Activities
Net income	$ 21,185	$ 19,259
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	5,719	6,268
Amortization of bond premiums	389	304
Provision for losses on accounts receivable, net of adjustments	(8)	102
Provision for excess and obsolete inventories, net	156	201
Share-based compensation	984	695
Excess tax benefits from stock options exercised and restricted stock awards vested	(680)	(385)
Gain on disposal of assets	(24)	(52)
Foreign currency transaction gain	0	43
Interest income on note receivable	(20)	(20)
Deferred income taxes	(1,961)	(1,966)
Write-off of note receivable	0	75
Changes in assets and liabilities:
Accounts receivable	(13,824)	(6,344)
Income tax receivable	1,753	3,942
Inventories	(4,624)	(1,718)
Prepaid expenses and other	(525)	(160)
Accounts payable	3,422	1,101
Deferred revenue	378	201
Accrued liabilities	5,185	6,194
Net cash provided by operating activities	17,505	27,740
Investing Activities
Capital expenditures	(5,903)	(1,949)
Proceeds from sale of property, plant and equipment	29	60
Investment in certificates of deposits	(9,220)	(958)
Maturities of certificates of deposits	3,904	1,440
Purchase of investments held to maturity	(5,955)	(9,969)
Maturities of investments	6,539	1,710
Proceeds from called investment	1,269	0
Principal payments from note receivable	35	40
Net cash used in investing activities	(9,302)	(9,626)
Financing Activities
Borrowings under revolving credit facility	0	2,321
Payments under revolving credit facility	0	(2,321)
Stock options exercised	632	767
Excess tax benefits from stock options exercised and restricted stock awards vested	680	385
Repurchase of stock	(5,116)	(3,010)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations	(3,804)	(1,858)
Net increase in cash and cash equivalents	4,399	16,256
Cash and cash equivalents, beginning of period	12,085	3,159
Cash and cash equivalents, end of period	$ 16,484	$ 19,415