CMC Materials (CCMP) 10-Q6 Aug 182018 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	CABOT MICROELECTRONICS CORP
Entity Central Index Key	1,102,934
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		25,551,252
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
UNAUDITED CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Revenue	$ 150,437	$ 127,957	$ 433,394	$ 370,395
Cost of goods sold	69,737	65,414	203,635	186,316
Gross profit	80,700	62,543	229,759	184,079
Operating expenses:
Research, development and technical	13,059	14,333	38,578	41,819
Selling and marketing	6,207	7,346	18,833	22,166
General and administrative	19,504	13,953	56,218	41,148
Total operating expenses	38,770	35,632	113,629	105,133
Operating income	41,930	26,911	116,130	78,946
Interest expense	513	1,117	2,803	3,402
Other income (expense), net	1,627	(115)	3,361	1,115
Income before income taxes	43,044	25,679	116,688	76,659
Provision for income taxes	7,873	5,740	54,863	16,209
Net income	$ 35,171	$ 19,939	$ 61,825	$ 60,450
Basic earnings per share (in dollars per share)	$ 1.37	$ 0.79	$ 2.42	$ 2.42
Weighted average basic shares outstanding (in shares)	25,611,505	25,228,468	25,479,078	24,941,190
Diluted earnings per share (in dollars per share)	$ 1.34	$ 0.77	$ 2.35	$ 2.37
Weighted average diluted shares outstanding (in shares)	26,318,638	25,720,715	26,221,864	25,449,507
Dividends per share (in dollars per share)	$ 0.40	$ 0.20	$ 1	$ 0.58

UNAUDITED CONSOLIDATED STATEME3

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 35,171	$ 19,939	$ 61,825	$ 60,450
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(8,829)	(2,635)	2,276	(6,326)
Net unrealized gain (loss) on available-for-sale securities	(48)	0	(48)	0
Net unrealized gain (loss) on cash flow hedges	(210)	1	(63)	819
Other comprehensive income (loss), net of tax	(9,087)	(2,634)	2,165	(5,507)
Comprehensive income	$ 26,084	$ 17,305	$ 63,990	$ 54,943

UNAUDITED CONSOLIDATED BALANCE

UNAUDITED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 186,124	$ 397,890
Available-for-sale securities	124,455	0
Accounts receivable, less allowance for doubtful accounts of $1,817 at June 30, 2018, and $1,747 at September 30, 2017	74,017	64,793
Inventories	77,302	71,873
Prepaid expenses and other current assets	29,008	16,426
Total current assets	490,906	550,982
Property, plant and equipment, net	108,569	106,361
Goodwill	101,059	101,932
Other intangible assets, net	36,982	42,710
Deferred income taxes	13,067	21,598
Other long-term assets	8,899	10,517
Total assets	759,482	834,100
Current liabilities:
Accounts payable	18,290	17,624
Current portion of long-term debt	0	10,938
Accrued expenses, income taxes payable and other current liabilities	72,009	62,651
Total current liabilities	90,299	91,213
Long-term debt, net of current portion, less prepaid debt issuance cost of $441 at September 30, 2017	0	132,997
Deferred income taxes	62	63
Other long-term liabilities	34,940	14,790
Total liabilities	125,301	239,063
Commitments and contingencies (Note 10)
Stockholders' equity:
Common Stock: Authorized: 200,000,000 shares, $0.001 par value; Issued: 35,806,136 shares at June 30, 2018, and 35,230,742 shares at September 30, 2017	36	35
Capital in excess of par value of common stock	615,543	580,938
Retained earnings	433,818	397,881
Accumulated other comprehensive income	6,114	3,949
Treasury stock at cost, 10,262,236 shares at June 30, 2018, and 9,948,190 shares at September 30, 2017	(421,330)	(387,766)
Total stockholders' equity	634,181	595,037
Total liabilities and stockholders' equity	$ 759,482	$ 834,100

UNAUDITED CONSOLIDATED BALANCE5

UNAUDITED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Current assets
Allowance for doubtful accounts	$ 1,817	$ 1,747
LIABILITIES AND STOCKHOLDERS' EQUITY
Long-term debt, prepaid debt issuance cost	$ 0	$ 441
Stockholders' equity
Common stock: authorized (in shares)	200,000,000	200,000,000
Common stock: par value (in dollars per share)	$ 0.001	$ 0.001
Common stock: issued (in shares)	35,806,136	35,230,742
Treasury stock at cost, shares (in shares)	10,262,236	9,948,190

UNAUDITED CONSOLIDATED STATEME6

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 61,825	$ 60,450
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,527	19,530
Provision for doubtful accounts	80	25
Share-based compensation expense	14,269	9,716
Deemed repatriation transition tax	24,641	0
Deferred income tax expense	9,280	2,081
Non-cash foreign exchange (gain)	(1,340)	470
Loss (gain) on disposal of property, plant and equipment	45	(621)
Impairment of assets	0	860
Realized loss on the sale of available-for-sale securities	117	0
(Gain) on sale of assets	(956)	0
Other	4,030	(323)
Changes in operating assets and liabilities:
Accounts receivable	(9,612)	(5,638)
Inventories	(5,526)	(247)
Prepaid expenses and other assets	(12,482)	(3,405)
Accounts payable	473	(1,186)
Accrued expenses, income taxes payable and other liabilities	(375)	8,304
Net cash provided by operating activities	103,996	90,016
Cash flows from investing activities:
Additions to property, plant and equipment	(15,245)	(15,901)
Proceeds from the sale of property, plant and equipment	0	637
Proceeds from the sale of assets	3,027	0
Purchases of available-for-sale securities	(178,412)	0
Proceeds from the sale and maturities of available-for-sale securities	55,194	175
Settlement of net investment hedge	(9,882)	0
Net cash used in investing activities	(145,318)	(15,089)
Cash flows from financing activities:
Repayment of long-term debt	(144,375)	(7,656)
Repurchases of common stock	(33,072)	(5,882)
Proceeds from issuance of stock	20,297	27,561
Dividends paid	(20,507)	(13,977)
Tax benefits associated with share-based compensation expense	0	5,826
Net cash provided by (used in) financing activities	(177,657)	5,872
Effect of exchange rate changes on cash	7,213	(4,376)
(Decrease) increase in cash and cash equivalents	(211,766)	76,423
Cash and cash equivalents at beginning of period	397,890	287,479
Cash and cash equivalents at end of period	186,124	363,902
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment in accrued liabilities and accounts payable at the end of the period	$ 1,588	$ 2,018

BACKGROUND AND BASIS OF PRESENT

BACKGROUND AND BASIS OF PRESENTATION	9 Months Ended
BACKGROUND AND BASIS OF PRESENTATION	Jun. 30, 2018
BACKGROUND AND BASIS OF PRESENTATION [Abstract]
BACKGROUND AND BASIS OF PRESENTATION	1. BACKGROUND AND BASIS OF PRESENTATION Cabot Microelectronics Corporation ("Cabot Microelectronics'', "the Company'', "us'', "we'', or "our'') supplies high-performance polishing slurries and pads used in the manufacture of advanced integrated circuit (IC) devices within the semiconductor industry, in a process called chemical mechanical planarization (CMP). CMP polishes surfaces at an atomic level, thereby helping to enable IC device manufacturers to produce smaller, faster and more complex IC devices with fewer defects. We develop, produce and sell CMP slurries for polishing many of the conducting and insulating materials used in IC devices. We develop, manufacture and sell CMP polishing pads, which are used in conjunction with slurries in the CMP process. We also develop and provide products for demanding surface modification applications in other industries through our Engineered Surface Finishes (ESF) business. For additional information, refer to Part 1, Item 1, "Business", in our Annual Report on Form 10-K for the fiscal year ended September 30, 2017. The unaudited Consolidated Financial Statements have been prepared by Cabot Microelectronics pursuant to the rules of the Securities and Exchange Commission (SEC) and accounting principles generally accepted in the United States of America (U.S. GAAP). In the opinion of management, these unaudited Consolidated Financial Statements include all adjustments, consisting of normal recurring adjustments, necessary for the fair statement of Cabot Microelectronics' financial position as of June 30, 2018, cash flows for the nine months ended June 30, 2018 and June 30, 2017, and results of operations for the three and nine months ended June 30, 2018 and June 30, 2017. The Consolidated Balance Sheets as of September 30, 2017 were derived from audited financial statements. The results of operations for the three and nine months ended June 30, 2018 may not be indicative of results to be expected for future periods, including the fiscal year ending September 30, 2018. This Report on Form 10-Q does not contain all of the footnote disclosures from the annual financial statements and should be read in conjunction with the Consolidated Financial Statements and related notes thereto included in Cabot Microelectronics' Annual Report on Form 10-K for the fiscal year ended September 30, 2017. The Consolidated Financial Statements include the accounts of Cabot Microelectronics and its subsidiaries. All intercompany transactions and balances between the companies have been eliminated as of June 30, 2018 USE OF ESTIMATES The preparation of financial statements and related disclosures in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in the Consolidated Financial Statements and accompanying notes. The accounting estimates that require management's most difficult and subjective judgments include, but are not limited to, those estimates related to bad debt expense, inventory valuation, valuation and classification of auction rate securities, impairment of long-lived assets and investments, business combinations, goodwill, other intangible assets, interest rate swaps, share-based compensation, income taxes and contingencies. We base our estimates on historical experience, current conditions and on various other assumptions that we believe are reasonable under the circumstances. However, future events are subject to change and estimates and judgments routinely require adjustment. Actual results may differ from these estimates under different assumptions or conditions. The results of operations for the quarter ended December 31, 2017 and nine months ended June 30, 2018 include a correction to prior period amounts, which we determined to be immaterial to the prior periods to which they relate and are expected to be immaterial to our fiscal 2018 results. The adjustments, relating primarily to accumulated earnings taxes of a foreign operation, increased the income tax expense for the first quarter of fiscal 2018 by $2,071. Separately, in Note 14 of this Report on Form 10-Q, we discuss the effects of the Tax Cuts and Jobs Act ("Tax Act") on our financial statements.

AVAILABLE-FOR-SALE-SECURITIES

AVAILABLE-FOR-SALE-SECURITIES	9 Months Ended
AVAILABLE-FOR-SALE-SECURITIES	Jun. 30, 2018
AVAILABLE FOR SALE SECURITIES [Abstract]
AVAILABLE-FOR-SALE SECURITIES	2. AVAILABLE-FOR-SALE SECURITIES Available-for-sale securities consist of the following as of June 30, 2018: Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Available-for-sale securities: Asset backed securities $ 13,900 $ 1 $ - $ 13,901 Certificates of deposit 2,439 3 - 2,442 Commercial paper 7,756 - (2 ) 7,754 Corporate debt securities 75,312 - (52 ) 75,260 U.S. Treasuries 25,094 4 - 25,098 Total available-for-sale securities $ 124,501 8 $ (54 ) $ 124,455 Available-for-sale securities, by contractual maturity, as of June 30, 2018 are as follows: Amortized Cost Estimated Fair Value Mature in one year or less $ 79,397 $ 79,373 Mature after one year through four years 45,104 45,082 $ 124,501 $ 124,455

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	9 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS	Jun. 30, 2018
FAIR VALUE OF FINANCIAL INSTRUMENTS [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	3. FAIR VALUE OF FINANCIAL INSTRUMENTS Fair value is defined as the price that would be received from the sale of an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Financial Accounting Standards Board ("FASB") established a three-level hierarchy for disclosure based on the extent and level of judgment used to estimate fair value. Level 1 inputs consist of valuations based on quoted market prices in active markets for identical assets or liabilities. Level 2 inputs consist of valuations based on quoted prices for similar assets or liabilities, quoted prices for identical assets or liabilities in an inactive market, or other observable inputs. Level 3 inputs consist of valuations based on unobservable inputs that are supported by little or no market activity. The following table presents financial instruments, other than long-term debt, that we measured at fair value on a recurring basis at June 30, 2018 and September 30, 2017. See Note 8 for a detailed discussion of our long-term debt. We have classified the following assets and liabilities in accordance with the fair value hierarchy set forth in the applicable standards. In instances where the inputs used to measure the fair value of an asset fall into more than one level of the hierarchy, we have classified them based on the lowest-level input that is significant to the determination of the fair value. June 30, 2018 Level 1 Level 2 Level 3 Total Fair Value Assets: Cash and cash equivalents $ 174,089 $ 12,035 $ - $ 186,124 Other long-term investments 1,089 - - 1,089 Available-for-sale securities: Asset Backed Securities 13,901 13,901 Certificates of Deposit 2,442 2,442 Commercial Paper 7,754 7,754 Corporate debt securities 75,260 75,260 U.S. Treasuries 25,098 25,098 Derivative financial instruments - 8 - 8 Total assets $ 175,178 $ 136,498 $ - $ 311,676 Liabilities: Derivative financial instruments - 44 - 44 Total liabilities $ - $ 44 $ - $ 44 September 30, 2017 Level 1 Level 2 Level 3 Total Fair Value Assets: Cash and cash equivalents $ 397,890 $ - $ - $ 397,890 Other long-term investments 929 - - 929 Derivative financial instruments - 263 - 263 Total assets $ 398,819 $ 263 $ - $ 399,082 Liabilities: Derivative financial instruments - 1,881 - 1,881 Total liabilities $ - $ 1,881 $ - $ 1,881 Our cash and cash equivalents consist of various bank accounts used to support our operations and investments in institutional money-market funds that are traded in active markets. We are invested exclusively in AAA-rated, prime institutional money market funds, comprised of high quality, fixed income securities. Our other long-term investments represent the fair value of investments under the Cabot Microelectronics Supplemental Employee Retirement Plan (SERP), which is a nonqualified supplemental savings plan. The fair value of the investments is determined through quoted market prices within actively traded markets. Although the investments are allocated to individual participants and investment decisions are made solely by those participants, the SERP is a nonqualified plan. Consequently, the Company owns the assets and the related offsetting liability for disbursement until a participant makes a qualifying withdrawal. The long-term investment was adjusted to $ 1,089 We use an investment pricing valuation methodology of a third-party service provider to determine fair values of our available-for-sale securities, consisting of fixed income securities that are under our managed investment arrangement; these are listed in Note 2 of this report on Form 10-Q. Our available-for-sale securities are valued using a market-based valuation methodology at the end of each reporting period. Market-based valuation is determined on the basis of the last reported sale price or market quotation, typically obtained from the third-party service provider. Market quotations may also include exchange trades and publicly-available bid/offer data from established market makers or quotation systems. All available-for-sale securities are classified as Level 2 based upon inputs other than quoted prices with observable market data.

INVENTORIES

INVENTORIES	9 Months Ended
INVENTORIES	Jun. 30, 2018
INVENTORIES [Abstract]
INVENTORIES	4. INVENTORIES Inventories consisted of the following: June 30, 2018 September 30, 2017 Raw materials $ 40,255 $ 36,415 Work in process 8,036 7,365 Finished goods 29,011 28,093 Total $ 77,302 $ 71,873

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	9 Months Ended
GOODWILL AND OTHER INTANGIBLE ASSETS	Jun. 30, 2018
GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	5. GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill was $101,059 as of June 30, 2018, and $101,932 as of September 30, 2017. The decrease in goodwill was due to $178 in foreign exchange fluctuations of the New Taiwan dollar, and a $695 decrease related to the sale of certain ESF assets. As a result of this sale of assets in March 2018, we received net proceeds of $3,277, of which $250 is held in escrow, and recorded a gain of $956 in other income in the Consolidated Statements of Income. The components of other intangible assets are as follows: June 30, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Other intangible assets subject to amortization: Product technology $ 46,273 $ 21,444 $ 42,287 $ 17,604 Acquired patents and licenses 8,270 8,250 8,270 8,241 Trade secrets and know-how 2,550 2,550 2,550 2,550 Customer relationships, distribution rights and other 28,061 17,098 28,229 15,421 Total other intangible assets subject to amortization 85,154 49,342 81,336 43,816 Other intangible assets not subject to amortization: In-process technology - 4,000 Other indefinite-lived intangibles* 1,170 1,190 Total other intangible assets not subject to amortization 1,170 5,190 Total other intangible assets $ 86,324 $ 49,342 $ 86,526 $ 43,816 *Other indefinite-lived intangible assets not subject to amortization consist primarily of trade names. During the first quarter of fiscal 2018, development of our in-process technology was completed, and we reclassified $4,000 to product technology under other intangible assets subject to amortization. Amortization expense on our intangible assets was $1,780 and $5,716 for the three and nine months ended June 30, 2018, respectively, and was $1,935 and $5,860 for the three and nine months ended June 30, 2017, respectively. Estimated future amortization expense for the five succeeding fiscal years is as follows: Fiscal Year Estimated Amortization Expense Remainder of 2018 $ 1,780 2019 7,119 2020 7,115 2021 7,108 2022 7,108 In the first quarter of fiscal 2018, we adopted We completed our annual impairment test during our fourth quarter of fiscal 2017 and concluded that no impairment existed. There were no indicators of potential impairment during the quarter ended June 30, 2018, so it was not necessary to perform an impairment review for goodwill and indefinite-lived intangible assets during the quarter. There have been no impairment charges recorded on the goodwill for any of our reporting units.

OTHER LONG-TERM ASSETS

OTHER LONG-TERM ASSETS	9 Months Ended
OTHER LONG-TERM ASSETS	Jun. 30, 2018
OTHER LONG-TERM ASSETS [Abstract]
OTHER LONG-TERM ASSETS	6. OTHER LONG-TERM ASSETS Other long-term assets consisted of the following: June 30, 2018 September 30, 2017 Auction rate securities (ARS) $ 3,975 $ 5,319 Long-term contract assets 1,809 2,115 Other long-term assets 2,026 2,154 Other long-term investments 1,089 929 Total $ 8,899 $ 10,517 Our ARS investment at June 30, 2018 consisted of one tax exempt municipal debt security with a par and fair value of $3,975 which has a maturity greater than ten years. The balance of our ARS investment decreased due to redemption of one of our securities during the quarter. The fair value of our ARS was determined using Level 2 fair value inputs. We have classified our ARS as held-to-maturity security based on our intention and ability to hold the security until maturity. There was no unrecognized gain or loss on our ARS investment during the quarter. Although we believe this security will ultimately be collected in full, we believe that it is not likely that we will be able to monetize the security in our next business cycle (which for us is generally one year). We will continue to monitor our ARS for impairment indicators, which may require us to record an impairment charge that is deemed other-than-temporary. In the third quarter of fiscal 2015, we amended a supply agreement with an existing supplier. The amended agreement includes a fee of $4,500, of which we already have paid $3,000, which provides us the option to purchase certain raw materials beyond calendar 2016 through the expiration of the agreement in December 2019. This fee was recorded as a long-term asset at its present value and is being amortized into cost of goods sold on a straight-line basis through the expiration date of the agreement. See Note 10 for more information regarding this agreement. Other long-term assets are comprised of the long-term portion of prepaid unamortized debt costs, related to our Revolving Credit Facility, as well as miscellaneous deposits and prepayments on contracts extending beyond the next twelve months. As discussed in Note 3, we recorded a long-term asset and a corresponding long-term liability of $ 1,089

ACCRUED EXPENSES, INCOME TAXES

ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES	9 Months Ended
	Jun. 30, 2018
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES [Abstract]
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES	7. ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES Accrued expenses, income taxes payable and other current liabilities consisted of the following: June 30, 2018 September 30, 2017 Accrued compensation $ 30,205 $ 35,332 Income taxes payable 14,255 9,717 Dividends payable 10,687 5,314 Goods and services received, not yet invoiced 3,763 2,172 Deferred revenue and customer advances 3,296 1,559 Warranty accrual 220 247 Taxes, other than income taxes 2,213 1,688 Current portion of long-term contract liability 1,473 1,500 Other accrued expenses 5,897 5,122 Total $ 72,009 $ 62,651

DEBT

DEBT	9 Months Ended
DEBT	Jun. 30, 2018
DEBT [Abstract]
DEBT	On February 13, 2012, we entered into a credit agreement (the "Credit Agreement") among the Company, as Borrower, Bank of America, N.A., as administrative agent, swing line lender and an L/C issuer, Bank of America, Merrill Lynch and J.P. Morgan Securities LLC, as joint lead arrangers and joint book managers, JPMorgan Chase Bank, N.A., as syndication agent, and Wells Fargo Bank, N.A. as documentation agent. The Credit Agreement provided us with a $175,000 term loan (the "Term Loan"), which we drew on February 27, 2012 to fund approximately half of the special cash dividend we paid to our stockholders on March 1, 2012, and a $100,000 revolving credit facility (the "Revolving Credit Facility"), which has never been drawn, with sub-limits for multicurrency borrowings, letters of credit and swing-line loans. The Term Loan and the Revolving Credit Facility are referred to as the "Credit Facilities." On June 27, 2014, we entered into an amendment (the "Amendment") to the Credit Agreement, which (i) increased term loan commitments by $17,500, from $157,500 to $175,000, the same level as the original amount under the Credit Agreement at its inception in 2012; (ii) increased the uncommitted accordion feature on the Revolving Credit Facility from $75,000 to $100,000; (iii) extended the expiration date of the Credit Facilities from February 13, 2017 to June 27, 2019; (iv) relaxed the consolidated leverage ratio financial covenant; and (v) revised certain pricing terms and other terms within the Credit Agreement. On June 27, 2014, we drew the $17,500 of increased term loan commitments, bringing the total outstanding commitments under the Term Loan to $175,000. The enactment of the Tax Act in the United States in December 2017 facilitated the repatriation of a substantial amount of the Company's non-U.S. cash. In April 2018, the Company paid off its remaining outstanding Term Loan pursuant to the Credit Agreement. There was no penalty upon the Company's prepayment of the Term Loan. As a result of this early extinguishment of the Term Loan, we expensed the remaining $315 of unamortized debt issuance cost in the third quarter of fiscal 2018. In conjunction with the payoff the Term Loan, we terminated the related interest rate swaps, and recognized a gain of $532 in the Consolidated Statements of Income. Although there are currently no borrowings on the Revolving Credit Facility, if we were to draw down on it, the borrowings under the amended Credit Facilities (other than in respect of swing-line loans) would bear interest at a rate per annum equal to the "Applicable Rate" (as defined below) plus, at our option, either (1) a LIBOR rate determined by reference to the cost of funds for deposits in the relevant currency for the interest period relevant to such borrowing or (2) the "Base Rate", which is the highest of (x) the prime rate of Bank of America, N.A., (y) the federal funds rate plus 1/2 of 1.00% and (z) the one-month LIBOR rate plus 1.00%. The current Applicable Rate for borrowings under the amended Credit Facilities is 1.50%, with respect to LIBOR borrowings and 0.25% with respect to Base Rate borrowings, with such Applicable Rate subject to adjustment based on our consolidated leverage ratio. Swing-line loans bear interest at the Base Rate plus the Applicable Rate for Base Rate loans under the Revolving Credit Facility. We pay a quarterly commitment fee to the lenders under the Revolving Credit Facility in respect of the unutilized commitments thereunder. As amended, the fee ranges from 0.20% to 0.30%, based on our consolidated leverage ratio. We also pay letter of credit fees as necessary. All obligations under the Credit Agreement are guaranteed by certain of our existing and future direct and indirect domestic subsidiaries. The obligations under the Credit Agreement and guarantees of those obligations are secured, subject to certain exceptions, by first priority liens and security interests in the assets of the Company and certain of its domestic subsidiaries. As of September 30, 2017, unamortized debt issuance costs related to our Term Loan that were presented as a reduction of long-term debt were $441, and these costs were subsequently recorded in interest expense upon payoff of the Term Loan. Unamortized debt issuance costs related to our Revolving Credit Facility were not material. The Credit Agreement contains covenants that restrict the ability of the Company and its subsidiaries to take certain actions, including, among other things and subject to certain significant exceptions: creating liens, incurring indebtedness, making investments, engaging in mergers, selling property, paying dividends or amending organizational documents. The Credit Agreement requires us to comply with certain financial ratio maintenance covenants. These include a maximum consolidated leverage ratio of 2.75 to 1.00 and a minimum consolidated fixed charge coverage ratio of 1.25 to 1.00 for the period January 1, 2016 through the expiration of the Credit Agreement. As of June 30, 2018, our consolidated leverage ratio was 0 3.74

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
DERIVATIVE FINANCIAL INSTRUMENTS	Jun. 30, 2018
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	9. DERIVATIVE FINANCIAL INSTRUMENTS We are exposed to various market risks, including risks associated with interest rates and foreign currency exchange rates. We enter into certain derivative transactions to mitigate the volatility associated with these exposures. We have policies in place that define acceptable instrument types we may enter into and we have established controls to limit our market risk exposure. We do not use derivative financial instruments for trading or speculative purposes. In addition, all derivatives, whether designated in hedging relationships or not, are required to be recorded on the Consolidated Balance Sheets at fair value on a gross basis. Cash Flow Hedges – Interest Rate Swap Agreements In the first quarter of fiscal 2015, we entered into floating-to-fixed interest rate swap agreements to hedge the variability in LIBOR-based interest payments on $86,406 of our outstanding variable rate debt. The notional amount of the swaps decreased each quarter by an amount in proportion to our scheduled quarterly principal payment of debt. The interest rate swap agreements were terminated during the third quarter of fiscal 2018 in conjunction with the payoff of the Term Loan. We designated these swap agreements as cash flow hedges pursuant to ASC 815, "Derivatives and Hedging". As cash flow hedges, unrealized gains were recognized as assets and unrealized losses were recognized as liabilities. Unrealized gains and losses were designated as effective or ineffective based on a comparison of the changes in fair value of the interest rate swaps and changes in fair value of the underlying exposures being hedged. The effective portion was recorded as a component of accumulated other comprehensive income or loss, while the ineffective portion was recorded as a component of interest expense. Changes in the method by which we paid interest from one-month LIBOR to another rate of interest could create ineffectiveness in the swaps and result in amounts which were reclassified from other comprehensive income into net income. Hedge effectiveness was tested quarterly to determine if hedge treatment continued to be appropriate. Foreign Currency Contracts Not Designated as Hedges On a regular basis, we enter into forward foreign exchange contracts in an effort to mitigate the risks associated with currency fluctuations on certain foreign currency balance sheet exposures. These foreign exchange contracts do not qualify for hedge accounting; therefore, the gains and losses resulting from the impact of currency exchange rate movements on our forward foreign exchange contracts are recognized as other income or expense in the accompanying consolidated income statements in the period in which the exchange rates change. As of June 30, 2018 and September 30, 2017, the notional amounts of the forward contracts we held to purchase U.S. dollars in exchange for foreign currencies were $7,907 and $8,176, respectively, and the notional amounts of forward contracts we held to sell U.S. dollars in exchange for foreign currencies were $20,825 and $24,295, respectively. Net Investment Hedge - Foreign Exchange Contracts In September 2017, we entered into two forward foreign exchange contracts in an effort to protect the net investment of our South Korean subsidiary against potential adverse changes resulting from currency fluctuations in the Korean won. We entered into forward contracts to sell 100 billion Korean won and buy U.S. dollars, settling in September 2022. We had designated these forward contracts as an effective net investment hedge. As a result of cash repatriation facilitated by the Tax Act , the Company terminated these foreign exchange contracts in the third quarter of fiscal 2018 Amounts recognized in the Consolidated Statements of Comprehensive Income for our net investment hedge during the nine months ended June 30, 2018 were as follows: Balance at September 30, 2017 $ 920 Loss on net investment hedge 8,440 Tax benefit (2,183 ) Balance at June 30, 2018 $ 7,177 The fair value of our derivative instruments included in the Consolidated Balance Sheets, which was determined using Level 2 inputs, was as follows: Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location June 30, 2018 September 30, 2017 June 30, 2018 September 30, 2017 Derivatives designated as hedging instruments Interest rate swap contracts Other long-term assets $ - $ 117 $ - $ - Accrued expenses, income taxes payable and other current liabilities $ - $ - $ - $ 31 Foreign exchange contracts designated as net investment hedge Other long-term liabilities $ - $ - $ - $ 1,442 Derivatives not designated as hedging instruments Foreign exchange contracts Prepaid expenses and other current assets $ 8 $ 146 $ - $ - Accrued expenses, income taxes payable and other current liabilities $ - $ - $ 44 $ 408 The following table summarizes the effect of our derivative instruments on our Consolidated Statements of Income for the three and nine months ended June 30, 2018 and 2017: Gain (Loss) Recognized in Statement of Income Three Months Ended Nine Months Ended Statement of Income Location June 30, 2018 June 30, 2017 June 30, 2018 June 30, 2017 Derivatives not designated as hedging instruments Foreign exchange contracts Other income, net $ (1,080 ) $ (235 ) $ (1,002 ) $ (1,709 ) We recorded a $532 gain in other income (expense) on our Consolidated Statements of Income as part of the termination of interest rate swap agreements.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
COMMITMENTS AND CONTINGENCIES	Jun. 30, 2018
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	10. COMMITMENTS AND CONTINGENCIES LEGAL PROCEEDINGS While we are not involved in any legal proceedings that we believe will have a material impact on our consolidated financial position, results of operations or cash flows, we periodically become a party to legal proceedings in the ordinary course of business. Refer to Note 18 of "Notes to the Consolidated Financial Statements" in Item 8 of Part II of our Annual Report on Form 10-K for the fiscal year ended September 30, 2017, for additional information regarding commitments and contingencies. POSTRETIREMENT OBLIGATIONS IN FOREIGN JURISDICTIONS We have defined benefit plans covering employees in certain foreign jurisdictions as required by local law, which are unfunded. Benefit costs, consisting primarily of service costs, are recorded as fringe benefit expense under cost of goods sold and operating expenses in our Consolidated Statements of Income. The projected benefit obligations and accumulated benefit obligations under all such unfunded plans are updated annually during the fourth quarter of the fiscal year. Benefit payments under all such unfunded plans to be paid over the next ten years are expected to be approximately $5,785. For more information regarding these plans, refer to Note 18 of "Notes to the Consolidated Financial Statements" included in Item 8 of Part II of our Annual Report on Form 10-K for the fiscal year ended September 30, 2017. PURCHASE OBLIGATIONS Purchase obligations include take-or-pay arrangements with suppliers, and purchase orders and other obligations entered into in the normal course of business regarding the purchase of goods and services. We have been operating under a fumed silica supply agreement with Cabot Corporation, our former parent company which is not a related party, the current term of which runs through December 2019. This agreement provides us the option to purchase fumed silica, with no minimum purchase requirements as of 2017, for which . The $1,500 payment due in 2019 is included in accrued expenses on our Consolidated Balance Sheets. As of June 30, 2018, purchase obligations include $ 1,502

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME	9 Months Ended
ACCUMULATED OTHER COMPREHENSIVE INCOME	Jun. 30, 2018
ACCUMULATED OTHER COMPREHENSIVE INCOME [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME	11. ACCUMULATED OTHER COMPREHENSIVE INCOME The table below summarizes the components of accumulated other comprehensive income (AOCI), net of tax provision/(benefit), as of June 30, 2018 and 2017: Foreign Currency Translation Cash Flow Hedges Pension and Other Postretirement Liabilities Available-for- Sale Securities Total Balance at September 30, 2017 $ 5,239 $ 46 $ (1,336 ) $ - $ 3,949 Foreign currency translation adjustment, net of tax of $(2,303) 2,276 - - - 2,276 Unrealized loss on available-for-sale securities, net of tax of $0 - - - (48 ) (48 ) Unrealized gain (loss) on cash flow hedges: Change in fair value, net of tax of $111 - 319 - - 319 Reclassification adjustment into earnings, net of tax of $(133) - (382 ) - - (382 ) Balance at June 30, 2018 $ 7,515 $ (17 ) $ (1,336 ) $ (48 ) $ 6,114 Foreign Currency Translation Cash Flow Hedges Pension and Other Postretirement Liabilities Total Balance at September 30, 2016 $ 11,985 $ (817 ) $ (1,612 ) $ 9,556 Foreign currency translation adjustment, net of tax of $(1,814) (6,326 ) - - (6,326 ) Unrealized gain (loss) on cash flow hedges: Change in fair value, net of tax of $610 - 1,088 - 1,088 Reclassification adjustment into earnings, net of tax of $(150) - (269 ) - (269 ) Balance at June 30, 2017 $ 5,659 $ 2 $ (1,612 ) $ 4,049 For the nine months ended June 30, 2018, we recorded $2,276 in currency translation gains, net of tax, primarily due to exchange rate fluctuations in the Japanese yen and Korean won versus the U.S. dollar, that are included in other comprehensive income. These gains and losses primarily relate to changes in the U.S. dollar value of assets and liabilities denominated in local currencies when these asset and liability amounts are translated at month-end exchange rates.

SHARE-BASED COMPENSATION PLANS

SHARE-BASED COMPENSATION PLANS	9 Months Ended
SHARE-BASED COMPENSATION PLANS	Jun. 30, 2018
SHARE-BASED COMPENSATION PLANS [Abstract]
SHARE-BASED COMPENSATION PLANS	12. We issue share-based awards under the following programs: our Cabot Microelectronics Corporation 2012 Omnibus Incentive Plan, as amended effective March 7, 2017 (OIP); our Cabot Microelectronics Corporation 2007 Employee Stock Purchase Plan, as Amended and Restated January 1, 2010 (ESPP); and, pursuant to the OIP, our Directors' Deferred Compensation Plan, as amended September 23, 2008 (DDCP), and our 2001 Executive Officer Deposit Share Program (DSP). In March 2017, our stockholders reapproved the material terms of performance-based awards under the OIP for purposes of complying with Section 162(m) of the Internal Revenue Code of 1986, as amended. Prior to March 2012, when our stockholders first approved the OIP, we issued share-based payments under our Second Amended and Restated Cabot Microelectronics Corporation 2000 Equity Incentive Plan, as amended and restated September 23, 2008 (EIP); our ESPP, and, pursuant to the EIP, the DDCP and DSP. For additional information regarding these programs, refer to Note 13 of "Notes to the Consolidated Financial Statements" included in Item 8 of Part II of our Annual Report on Form 10-K for the fiscal year ended September 30, 2017. Other than the ESPP, all share-based payments granted beginning March 6, 2012 are made from the OIP, and since then, the EIP no longer has been available for any awards. We record share-based compensation expense for all share-based awards, including stock option grants, and restricted stock, restricted stock unit and performance share unit ("PSU") awards, and employee stock purchase plan purchases. We calculate share-based compensation expense using the straight-line approach based on awards ultimately expected to vest, which requires the use of an estimated forfeiture rate. Our estimated forfeiture rate is primarily based on historical experience, but may be revised in future periods if actual forfeitures differ from the estimate. We use the Black-Scholes option-pricing model to estimate the grant date fair value of our stock options and employee stock purchase plan purchases. This model requires the input of highly subjective assumptions, including the price volatility of the underlying stock, the expected term of our stock options, expected dividend yield and the risk-free interest rate. We estimate the expected volatility of our stock options based on a combination of our stock's historical volatility and the implied volatilities from actively-traded options on our stock. We calculate the expected term of our stock options using historical stock option exercise data, and for stock option grants made prior to December 2017, we have added a slight premium to this expected term for employees who meet the definition of retirement-eligible pursuant to their stock option grants during the contractual term of the grant. As of December 2017, the provisions of new stock option grants and restricted stock unit awards state that except in certain circumstances including termination for cause, once an employee meets the retirement eligibility requirements, any remaining unvested share-based awards will continue to vest regardless of termination of service. Consequently, the requisite service period for the award is satisfied upon retirement eligibility. Therefore, for those employees who have met the retirement eligibility at the grant date, we now record the total share-based compensation expense upon award; for those employees who will meet the retirement eligibility during the four-year vesting period, we now record the share-based compensation expense over the period from the grant date through the date of retirement eligibility, rather than over the four-year vesting period stated in the award agreement. The expected dividend yield represents our annualized dividend in dollars divided by the stock price on the date of grant. The risk-free interest rate is derived from the U.S. Treasury yield curve in effect at the time of grant. The PSUs that have been awarded may be subject to downward or upward adjustment depending on the total shareholder return achieved by the Company during the particular performance period related to the PSUs, relative to the total shareholder return of the S&P SmallCap 600 Index. We use a third-party service provider to estimate the fair value of the PSUs at grant date by using a Monte Carlo simulation model. This model simulates the stock price movements of the Company and Index constituents using certain assumptions, including the stock price of our company and Index constituents, the risk-free interest rate and stock price volatility. In the first quarter of fiscal 2018, we adopted ASU No. 2016-09, "Improvements to Employee Share Based Payment Accounting" (Topic 718) (ASU 2016-09) prospectively. The provisions of this standard relate to aspects of the accounting for share-based payments transactions, including income tax consequences, classification of awards as either equity or liabilities, classification of excess tax benefits on the Consolidated Statements of Cash Flows and earnings per share calculations. Upon adoption, we recorded a tax benefit of $2,806 in our Consolidated Statements of Income. The net income, including the impact of the tax benefits, was used to calculate our basic earnings per share under the new guidance. In addition, we have elected to continue to estimate forfeitures under ASC 718 pursuant to the adoption of ASU 2016-09. Share-based compensation expense for the three and nine months ended June 30, 2018 and 2017, was as follows: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Cost of goods sold $ 542 $ 577 $ 1,896 $ 1,670 Research, development and technical 445 444 1,491 1,322 Selling and marketing 290 346 961 1,032 General and administrative 2,909 1,884 9,921 5,692 Total share-based compensation expense 4,186 3,251 14,269 9,716 Tax benefit (1,023 ) (1,052 ) (3,272 ) (3,219 ) Total share-based compensation expense, net of tax $ 3,163 $ 2,199 $ 10,997 $ 6,497

OTHER INCOME, NET

OTHER INCOME, NET	9 Months Ended
OTHER INCOME, NET	Jun. 30, 2018
OTHER INCOME, NET [Abstract]
OTHER INCOME, NET	13. OTHER INCOME (EXPENSE), NET Other income (expense), net, consisted of the following: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Interest income $ 1,141 $ 659 $ 3,248 $ 1,596 Other income (expense) 486 (774 ) 113 (481 ) Total other income (expense), net $ 1,627 $ (115 ) $ 3,361 $ 1,115

INCOME TAXES

INCOME TAXES	9 Months Ended
INCOME TAXES	Jun. 30, 2018
INCOME TAXES [Abstract]
INCOME TAXES	14. INCOME TAXES The Tax Act includes broad and complex changes to the U.S. tax code, including but not limited to: (1) reducing the U.S. federal corporate income tax rate to 21% effective January 1, 2018; and (2) requiring a one-time transition tax on certain un-repatriated earnings of foreign subsidiaries that is payable over eight years. For fiscal 2018, we are recording our income tax provision using a blended U.S. statutory tax rate of 24.5%, which is based on a proration of the applicable tax rates before and after the Tax Act. The U.S. statutory tax rate of 21% will apply for fiscal 2019 and beyond. As a result of the Tax Act, the SEC staff issued accounting guidance that provides up to a one-year measurement period during which a company may complete its accounting for the impacts of the Tax Act (SAB 118). To the extent that a company's accounting for certain income tax effects of the Tax Act is incomplete but for which the company is able to determine a reasonable estimate, it must record a provisional estimate in its financial statements. If a company cannot determine a provisional estimate to be included in its financial statements, it should continue to apply the provisions of the tax laws that were in effect immediately before the enactment of the Tax Act. In connection with our initial analysis of the impact of the Tax Act, we recorded provisional discrete tax expense of $32,880 in the quarter ended December 31, 2017. During the second and third quarters of fiscal 2018, we recorded a reduction of $299 for a change in estimated withholding taxes and the re-measurement of U.S. deferred tax assets and liabilities. For various reasons that are discussed more fully below, we have not completed our accounting for the income tax effects of certain elements of the Tax Act, but we have recorded the following provisional estimates. Deemed Repatriation Transition Tax Reduction of U.S. Federal Corporate Tax Rate The Company is also analyzing other provisions of the Tax Act to determine their impact on the Company's effective tax rate in fiscal year 2018 or in the future, including the following: Global Intangible Low Taxed Income (GILTI): Base Erosion and Anti-Abuse Tax (BEAT): Foreign Derived Intangible Income (FDII): The Company previously operated under a tax holiday in South Korea in fiscal years 2013 through 2017 in conjunction with our investment in research, development and manufacturing facilities there, which expired at the end of fiscal year 2017. This arrangement allowed for a tax at 50% of the local statutory rate in effect for fiscal years 2016 and 2017, following a 0% tax rate in fiscal years 2013, 2014 and 2015. This tax holiday reduced our income tax provision by approximately $3,094 and increased our diluted earnings per share by approximately $0.12 during the nine months ended June 30, 2017.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
EARNINGS PER SHARE	Jun. 30, 2018
EARNINGS PER SHARE [Abstract]
EARNINGS PER SHARE	15. EARNINGS PER SHARE Basic earnings per share (EPS) is calculated by dividing net income available to common stockholders by the weighted-average number of common shares outstanding during the period, excluding the effects of unvested restricted stock awards that have a right to receive non-forfeitable dividends, which are considered participating securities as prescribed by the two-class method under ASC 260 "Earnings per Share". Diluted EPS is calculated in a similar manner, but the weighted-average number of common shares outstanding during the period is increased to include the weighted-average dilutive effect of "in-the-money" stock options and unvested restricted stock shares using the treasury stock method. Pursuant to the adoption of ASU 2016-09 in the first quarter of fiscal 2018, the tax benefits associated with share-based compensation plans were recorded as a tax benefit in our Consolidated Statements of Income. The number of shares that would be repurchased with the proceeds from the tax benefits was excluded from the diluted weighted average shares outstanding using treasury stock method under the new guidance. The standards of accounting for earnings per share require companies to provide a reconciliation of the numerator and denominator of the basic and diluted earnings per share computations. Basic and diluted earnings per share were calculated as follows: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Numerator: Net Income $ 35,171 $ 19,939 $ 61,825 60,450 Less: income attributable to participating securities (34 ) (52 ) (73 ) (191 ) Earnings available to common shares $ 35,137 $ 19,887 $ 61,752 60,259 Denominator: Weighted average common shares 25,611,505 25,228,468 25,479,078 24,941,190 (Denominator for basic calculation) Weighted average effect of dilutive securities: Share-based compensation 707,133 492,247 742,786 508,317 Diluted weighted average common shares 26,318,638 25,720,715 26,221,864 25,449,507 (Denominator for diluted calculation) Earnings per share: Basic $ 1.37 $ 0.79 $ 2.42 2.42 Diluted $ 1.34 $ 0.77 $ 2.35 2.37 For both the three months ended June 30, 2018 For the nine months ended June 30, 2018

FINANCIAL INFORMATION BY INDUST

FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE	9 Months Ended
FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE	Jun. 30, 2018
FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE [Abstract]
FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE	16. FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE We operate predominantly in one reportable segment, as defined under ASC 280 "Segment Reporting" – the development, manufacture, and sale of CMP consumables. Revenue generated by product line for the three and nine months ended June 30, 2018 and 2017, was as follows: Three Months Ended June 30, Nine Months Ended June 30, Revenue: 2018 2017 2018 2017 Tungsten slurries $ 64,313 $ 54,731 $ 187,618 $ 161,867 Dielectric slurries 36,616 30,266 102,877 87,391 Polishing pads 20,918 17,599 60,813 50,947 Other metals slurries 18,124 16,090 51,476 46,540 ESF and other 10,466 9,271 30,610 23,650 Total revenue $ 150,437 $ 127,957 $ 433,394 $ 370,395

NEW ACCOUNTING PRONOUNCEMENTS

NEW ACCOUNTING PRONOUNCEMENTS	9 Months Ended
NEW ACCOUNTING PRONOUNCEMENTS	Jun. 30, 2018
NEW ACCOUNTING PRONOUNCEMENTS [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	17. NEW ACCOUNTING PRONOUNCEMENTS In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers" (Topic 606), an updated standard on revenue recognition . In July 2015, the FASB issued ASU No, 2015-11, "Simplifying the Measurement of Inventory" (Topic 330). The provisions of ASU 2015-11 require an entity to measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We adopted ASU 2015-11 effective October 1, 2017, and this pronouncement had no material effect on our financial statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases" (Topic 842). The provisions of ASU 2016-02 require a dual approach for lessee accounting under which a lessee would recognize a right-of-use asset and a corresponding lease liability. Leases will be classified as either finance or operating leases. For finance leases, a lessee will recognize interest expense and amortization of the right-of-use asset, and for operating leases, the lessee will recognize a straight-line total lease expense. The guidance also requires qualitative and specific quantitative disclosures to supplement the amounts recorded in the financial statements, to afford better understanding of an entity's leasing activities, including any significant judgments and estimates. ASU 2016-02 will be effective for us beginning October 1, 2019, but early adoption is permitted. We are currently evaluating the impact of implementation of this standard on our financial statements. In March 2016, the FASB issued ASU No. 2016-05, "Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships" (Topic 815). The provisions of ASU 2016-05 provide clarification that a change in a counterparty of a derivative instrument that has been designated as a hedging instrument does not require dedesignation of that hedging relationship, provided that all other hedge accounting criteria is met. ASU 2016-05 will be effective for us beginning October 1, 2018, but early adoption is permitted. We do not believe the adoption of this standard will have a material effect on our financial statements. In March 2016, the FASB issued ASU No. 2016-07, "Simplifying the Transition to the Equity Method of Accounting" (Topic 323). The provisions of ASU 2016-07 require equity method investors to add the cost of acquiring additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method prospectively as of the date the investment qualifies for the equity method of accounting. ASU 2016-07 will be effective for us beginning October 1, 2018, but early adoption is permitted. We do not believe the adoption of this standard will have a material effect on our financial statements as we currently have no equity method investments. In June 2016, the FASB issued ASU No. 2016-13, "Measurement of Credit Losses on Financial Instruments" (Topic 326). The provisions of this standard require financial assets measured at amortized cost to be presented at the net amount expected to be collected. An allowance account would be established to present the net carrying value at the amount expected to be collected. ASU 2016-13 also provides that credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. ASU 2016-13 will be effective for us beginning October 1, 2020, but early adoption is permitted as of October 1, 2019. We are currently evaluating the impact of implementation of this standard on our financial statements. In August 2016, the FASB issued ASU No. 2016-15 "Classification of Certain Cash Receipts and Cash Payments" (Topic 230). The provisions of this standard provide guidance on the classification within the Consolidated Statements of Cash Flows of certain types of cash receipts and cash payments in an effort to eliminate diversity in practice. ASU 2016-15 will be effective for us beginning October 1, 2018, but early adoption is permitted. We do not believe the adoption of this standard will have a material effect on our financial statements as we currently do not have any of the cash receipts or payments discussed in this standard. In October 2016, the FASB issued ASU No. 2016-16 "Intra-Entity Transfers of Assets Other Than Inventory" (Topic 740). The provisions of this standard provide guidance on recognition of taxes related to intra-entity transfer of assets other than inventory when the transfer occurs. ASU 2016-16 will be effective for us beginning October 1, 2018, but early adoption is permitted. We are currently evaluating the impact of implementation of this standard on our financial statements. In October 2016, the FASB issued ASU No. 2016-17 "Interest Held through Related Parties That Are under Common Control" (Topic 810). The provisions of this standard provide further guidance related to ASU 2015-02, and provide guidance on consolidation in relation to Variable Interest Entities (VIEs) and related parties. We adopted ASU 2016-17 effective October 1, 2017, and this pronouncement had no material effect on our financial statements as we currently have no interest in any entities that may be considered VIEs. In January 2017, the FASB issued ASU No. 2017-01 "Clarifying the Definition of a Business" (Topic 805). The provisions of this standard provide guidance to determine whether the acquisition or sale of a set of assets or activities constitutes a business. The standard requires that an integrated set of assets and activities include an input and a substantive process that together contribute to the ability to create output. We adopted ASU 2017-01 effective October 1, 2017, and this pronouncement had no material effect on our financial statements. In January 2017, the FASB issued ASU No. 2017-04 "Simplifying the Test for Goodwill Impairment" (Topic 350). The provisions of this standard eliminate Step 2 from the goodwill impairment test, which required an entity to determine the fair value of its assets and liabilities at the impairment testing date of its goodwill and compare it to its carrying amount to determine a possible impairment loss. Goodwill impairment quantification will now be done by comparing the fair value of a reporting unit and its carrying amount. We adopted ASU 2017-04 effective October 1, 2017 and we will apply the new guidance in our annual test for goodwill impairment in the fourth quarter of fiscal 2018. In March 2017, the FASB issued ASU No. 2017-07 "Improving the Presentation of Net Period Pension Cost and Net Period Postretirement Benefit Cost" (Topic 715). The provisions of ASU 2017-07 provided specific guidance on the presentation of the components of net benefit cost. ASU 2017-07 will be effective for us beginning October 1, 2018. We are currently evaluating the impact of implementation of this standard on our financial statements. In May 2017, the FASB issued ASU No. 2017-09 "Scope of Modification Accounting" (Topic 718). The provisions of ASU 2017-09 provide specific guidance about which changes to the term or conditions of a share-based payment require an entity to apply modification accounting. ASU 2017-09 will be effective for us beginning October 1, 2018. We are currently evaluating the impact of implementation of this standard on our financial statements. In August 2017, the FASB issued ASU No. 2017-12 "Derivatives and Hedging" (Topic 815). The provisions of this standard amend the hedge accounting model in ASC 815 to expand an entity's ability to hedge nonfinancial and financial risk components, reduce complexity in fair value hedges of interest rate risk, eliminate the requirement to separately measure and report hedge ineffectiveness, and generally require the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also eases certain documentation and assessment requirements and modifies the accounting for components excluded from the assessment of hedge effectiveness. ASU 2017-12 will be effective for us beginning October 1, 2019, but early adoption is permitted. We are currently evaluating the impact of implementation of this standard on our financial statements. In February 2018, the FASB issued ASU No. 2018-02 "Income Statement – Reporting Comprehensive Income (Topic 220)". The amendments in this standard allow a company to reclassify the stranded tax effects resulting from the Tax Act from accumulated other comprehensive income to retained earnings. ASU 2018-02 will be effective for us beginning October 1, 2019, but early adoption is permitted. We are currently evaluating the impact of implementation of this standard on our financial statements. In June 2018, the FASB issued ASU No. 2018-07 " Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting". The ASU simplified the accounting for share-based payments granted to nonemployees for goods and services, therefore guidance on such payments to nonemployees would be mostly aligned with the requirements for share-based payments granted to employees. ASU 2018-07 will be effective for us beginning October 1, 2019, but early adoption is permitted (but no earlier than the adoption date of Topic 606). We are currently evaluating the impact of implementation of this standard on our financial statements.

BACKGROUND AND BASIS OF PRESE24

BACKGROUND AND BASIS OF PRESENTATION (Policies)	9 Months Ended
BACKGROUND AND BASIS OF PRESENTATION (Policies)	Jun. 30, 2018
BACKGROUND AND BASIS OF PRESENTATION [Abstract]
Use of Estimates	USE OF ESTIMATES The preparation of financial statements and related disclosures in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in the Consolidated Financial Statements and accompanying notes. The accounting estimates that require management's most difficult and subjective judgments include, but are not limited to, those estimates related to bad debt expense, inventory valuation, valuation and classification of auction rate securities, impairment of long-lived assets and investments, business combinations, goodwill, other intangible assets, interest rate swaps, share-based compensation, income taxes and contingencies. We base our estimates on historical experience, current conditions and on various other assumptions that we believe are reasonable under the circumstances. However, future events are subject to change and estimates and judgments routinely require adjustment. Actual results may differ from these estimates under different assumptions or conditions.

AVAILABLE-FOR-SALE-SECURITIES (

AVAILABLE-FOR-SALE-SECURITIES (Tables)	9 Months Ended
AVAILABLE-FOR-SALE-SECURITIES (Tables)	Jun. 30, 2018
AVAILABLE FOR SALE SECURITIES [Abstract]
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	Available-for-sale securities consist of the following as of June 30, 2018: Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Available-for-sale securities: Asset backed securities $ 13,900 $ 1 $ - $ 13,901 Certificates of deposit 2,439 3 - 2,442 Commercial paper 7,756 - (2 ) 7,754 Corporate debt securities 75,312 - (52 ) 75,260 U.S. Treasuries 25,094 4 - 25,098 Total available-for-sale securities $ 124,501 8 $ (54 ) $ 124,455
Investments Classified by Contractual Maturity Date [Table Text Block]	Available-for-sale securities, by contractual maturity, as of June 30, 2018 are as follows: Amortized Cost Estimated Fair Value Mature in one year or less $ 79,397 $ 79,373 Mature after one year through four years 45,104 45,082 $ 124,501 $ 124,455

FAIR VALUE OF FINANCIAL INSTR26

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	Jun. 30, 2018
FAIR VALUE OF FINANCIAL INSTRUMENTS [Abstract]
Fair Value of Financial Instruments	The following table presents financial instruments, other than long-term debt, that we measured at fair value on a recurring basis at June 30, 2018 and September 30, 2017. See Note 8 for a detailed discussion of our long-term debt. We have classified the following assets and liabilities in accordance with the fair value hierarchy set forth in the applicable standards. In instances where the inputs used to measure the fair value of an asset fall into more than one level of the hierarchy, we have classified them based on the lowest-level input that is significant to the determination of the fair value. June 30, 2018 Level 1 Level 2 Level 3 Total Fair Value Assets: Cash and cash equivalents $ 174,089 $ 12,035 $ - $ 186,124 Other long-term investments 1,089 - - 1,089 Available-for-sale securities: Asset Backed Securities 13,901 13,901 Certificates of Deposit 2,442 2,442 Commercial Paper 7,754 7,754 Corporate debt securities 75,260 75,260 U.S. Treasuries 25,098 25,098 Derivative financial instruments - 8 - 8 Total assets $ 175,178 $ 136,498 $ - $ 311,676 Liabilities: Derivative financial instruments - 44 - 44 Total liabilities $ - $ 44 $ - $ 44 September 30, 2017 Level 1 Level 2 Level 3 Total Fair Value Assets: Cash and cash equivalents $ 397,890 $ - $ - $ 397,890 Other long-term investments 929 - - 929 Derivative financial instruments - 263 - 263 Total assets $ 398,819 $ 263 $ - $ 399,082 Liabilities: Derivative financial instruments - 1,881 - 1,881 Total liabilities $ - $ 1,881 $ - $ 1,881

INVENTORIES (Tables)

INVENTORIES (Tables)	9 Months Ended
INVENTORIES (Tables)	Jun. 30, 2018
INVENTORIES [Abstract]
Inventories	Inventories consisted of the following: June 30, 2018 September 30, 2017 Raw materials $ 40,255 $ 36,415 Work in process 8,036 7,365 Finished goods 29,011 28,093 Total $ 77,302 $ 71,873

GOODWILL AND OTHER INTANGIBLE28

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	9 Months Ended
GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	Jun. 30, 2018
GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
Other Intangible Assets	The components of other intangible assets are as follows: June 30, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Other intangible assets subject to amortization: Product technology $ 46,273 $ 21,444 $ 42,287 $ 17,604 Acquired patents and licenses 8,270 8,250 8,270 8,241 Trade secrets and know-how 2,550 2,550 2,550 2,550 Customer relationships, distribution rights and other 28,061 17,098 28,229 15,421 Total other intangible assets subject to amortization 85,154 49,342 81,336 43,816 Other intangible assets not subject to amortization: In-process technology - 4,000 Other indefinite-lived intangibles* 1,170 1,190 Total other intangible assets not subject to amortization 1,170 5,190 Total other intangible assets $ 86,324 $ 49,342 $ 86,526 $ 43,816
Estimated Future Amortization Expense for the Succeeding Five Fiscal Years	Amortization expense on our intangible assets was $1,780 and $5,716 for the three and nine months ended June 30, 2018, respectively, and was $1,935 and $5,860 for the three and nine months ended June 30, 2017, respectively. Estimated future amortization expense for the five succeeding fiscal years is as follows: Fiscal Year Estimated Amortization Expense Remainder of 2018 $ 1,780 2019 7,119 2020 7,115 2021 7,108 2022 7,108

OTHER LONG-TERM ASSETS (Tables)

OTHER LONG-TERM ASSETS (Tables)	9 Months Ended
OTHER LONG-TERM ASSETS (Tables)	Jun. 30, 2018
OTHER LONG-TERM ASSETS [Abstract]
Other Long Term Assets	Other long-term assets consisted of the following: June 30, 2018 September 30, 2017 Auction rate securities (ARS) $ 3,975 $ 5,319 Long-term contract assets 1,809 2,115 Other long-term assets 2,026 2,154 Other long-term investments 1,089 929 Total $ 8,899 $ 10,517

ACCRUED EXPENSES, INCOME TAXE30

ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES (Tables)	9 Months Ended
	Jun. 30, 2018
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES [Abstract]
Accrued Expenses, Income Taxes Payable and Other Current Liabilities	Accrued expenses, income taxes payable and other current liabilities consisted of the following: June 30, 2018 September 30, 2017 Accrued compensation $ 30,205 $ 35,332 Income taxes payable 14,255 9,717 Dividends payable 10,687 5,314 Goods and services received, not yet invoiced 3,763 2,172 Deferred revenue and customer advances 3,296 1,559 Warranty accrual 220 247 Taxes, other than income taxes 2,213 1,688 Current portion of long-term contract liability 1,473 1,500 Other accrued expenses 5,897 5,122 Total $ 72,009 $ 62,651

DERIVATIVE FINANCIAL INSTRUME31

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	Jun. 30, 2018
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
Amounts Recognized in Consolidated Statements of Comprehensive Income for Net Investment Hedge	Amounts recognized in the Consolidated Statements of Comprehensive Income for our net investment hedge during the nine months ended June 30, 2018 were as follows: Balance at September 30, 2017 $ 920 Loss on net investment hedge 8,440 Tax benefit (2,183 ) Balance at June 30, 2018 $ 7,177
FV of Derivative Instruments in the Consolidated Balance Sheet	The fair value of our derivative instruments included in the Consolidated Balance Sheets, which was determined using Level 2 inputs, was as follows: Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location June 30, 2018 September 30, 2017 June 30, 2018 September 30, 2017 Derivatives designated as hedging instruments Interest rate swap contracts Other long-term assets $ - $ 117 $ - $ - Accrued expenses, income taxes payable and other current liabilities $ - $ - $ - $ 31 Foreign exchange contracts designated as net investment hedge Other long-term liabilities $ - $ - $ - $ 1,442 Derivatives not designated as hedging instruments Foreign exchange contracts Prepaid expenses and other current assets $ 8 $ 146 $ - $ - Accrued expenses, income taxes payable and other current liabilities $ - $ - $ 44 $ 408
Effect of Derivative Instruments on the Consolidated Statement of Income	The following table summarizes the effect of our derivative instruments on our Consolidated Statements of Income for the three and nine months ended June 30, 2018 and 2017: Gain (Loss) Recognized in Statement of Income Three Months Ended Nine Months Ended Statement of Income Location June 30, 2018 June 30, 2017 June 30, 2018 June 30, 2017 Derivatives not designated as hedging instruments Foreign exchange contracts Other income, net $ (1,080 ) $ (235 ) $ (1,002 ) $ (1,709 )

ACCUMULATED OTHER COMPREHENSI32

ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	9 Months Ended
ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	Jun. 30, 2018
ACCUMULATED OTHER COMPREHENSIVE INCOME [Abstract]
Accumulated Other Comprehensive Income	The table below summarizes the components of accumulated other comprehensive income (AOCI), net of tax provision/(benefit), as of June 30, 2018 and 2017: Foreign Currency Translation Cash Flow Hedges Pension and Other Postretirement Liabilities Available-for- Sale Securities Total Balance at September 30, 2017 $ 5,239 $ 46 $ (1,336 ) $ - $ 3,949 Foreign currency translation adjustment, net of tax of $(2,303) 2,276 - - - 2,276 Unrealized loss on available-for-sale securities, net of tax of $0 - - - (48 ) (48 ) Unrealized gain (loss) on cash flow hedges: Change in fair value, net of tax of $111 - 319 - - 319 Reclassification adjustment into earnings, net of tax of $(133) - (382 ) - - (382 ) Balance at June 30, 2018 $ 7,515 $ (17 ) $ (1,336 ) $ (48 ) $ 6,114 Foreign Currency Translation Cash Flow Hedges Pension and Other Postretirement Liabilities Total Balance at September 30, 2016 $ 11,985 $ (817 ) $ (1,612 ) $ 9,556 Foreign currency translation adjustment, net of tax of $(1,814) (6,326 ) - - (6,326 ) Unrealized gain (loss) on cash flow hedges: Change in fair value, net of tax of $610 - 1,088 - 1,088 Reclassification adjustment into earnings, net of tax of $(150) - (269 ) - (269 ) Balance at June 30, 2017 $ 5,659 $ 2 $ (1,612 ) $ 4,049

SHARE-BASED COMPENSATION PLANS

SHARE-BASED COMPENSATION PLANS (Tables)	9 Months Ended
SHARE-BASED COMPENSATION PLANS (Tables)	Jun. 30, 2018
SHARE-BASED COMPENSATION PLANS [Abstract]
Share Based Compensation Expense	Share-based compensation expense for the three and nine months ended June 30, 2018 and 2017, was as follows: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Cost of goods sold $ 542 $ 577 $ 1,896 $ 1,670 Research, development and technical 445 444 1,491 1,322 Selling and marketing 290 346 961 1,032 General and administrative 2,909 1,884 9,921 5,692 Total share-based compensation expense 4,186 3,251 14,269 9,716 Tax benefit (1,023 ) (1,052 ) (3,272 ) (3,219 ) Total share-based compensation expense, net of tax $ 3,163 $ 2,199 $ 10,997 $ 6,497

OTHER INCOME, NET (Tables)

OTHER INCOME, NET (Tables)	9 Months Ended
OTHER INCOME, NET (Tables)	Jun. 30, 2018
OTHER INCOME, NET [Abstract]
Other Income, Net	Other income (expense), net, consisted of the following: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Interest income $ 1,141 $ 659 $ 3,248 $ 1,596 Other income (expense) 486 (774 ) 113 (481 ) Total other income (expense), net $ 1,627 $ (115 ) $ 3,361 $ 1,115

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
EARNINGS PER SHARE (Tables)	Jun. 30, 2018
EARNINGS PER SHARE [Abstract]
Basic and Diluted Earnings per Share	The standards of accounting for earnings per share require companies to provide a reconciliation of the numerator and denominator of the basic and diluted earnings per share computations. Basic and diluted earnings per share were calculated as follows: Three Months Ended June 30, Nine Months Ended June 30, 2018 2017 2018 2017 Numerator: Net Income $ 35,171 $ 19,939 $ 61,825 60,450 Less: income attributable to participating securities (34 ) (52 ) (73 ) (191 ) Earnings available to common shares $ 35,137 $ 19,887 $ 61,752 60,259 Denominator: Weighted average common shares 25,611,505 25,228,468 25,479,078 24,941,190 (Denominator for basic calculation) Weighted average effect of dilutive securities: Share-based compensation 707,133 492,247 742,786 508,317 Diluted weighted average common shares 26,318,638 25,720,715 26,221,864 25,449,507 (Denominator for diluted calculation) Earnings per share: Basic $ 1.37 $ 0.79 $ 2.42 2.42 Diluted $ 1.34 $ 0.77 $ 2.35 2.37

FINANCIAL INFORMATION BY INDU36

FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE (Tables)	9 Months Ended
	Jun. 30, 2018
FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE [Abstract]
Revenue Generated by Product Line	Revenue generated by product line for the three and nine months ended June 30, 2018 and 2017, was as follows: Three Months Ended June 30, Nine Months Ended June 30, Revenue: 2018 2017 2018 2017 Tungsten slurries $ 64,313 $ 54,731 $ 187,618 $ 161,867 Dielectric slurries 36,616 30,266 102,877 87,391 Polishing pads 20,918 17,599 60,813 50,947 Other metals slurries 18,124 16,090 51,476 46,540 ESF and other 10,466 9,271 30,610 23,650 Total revenue $ 150,437 $ 127,957 $ 433,394 $ 370,395

BACKGROUND AND BASIS OF PRESE37

BACKGROUND AND BASIS OF PRESENTATION (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
BACKGROUND AND BASIS OF PRESENTATION [Abstract]
Immaterial error correction		The results of operations for the quarter ended December 31, 2017 and nine months ended June 30, 2018 include a correction to prior period amounts, which we determined to be immaterial to the prior periods to which they relate and are expected to be immaterial to our fiscal 2018 results. The adjustments, relating primarily to accumulated earnings taxes of a foreign operation, increased the income tax expense for the first quarter of fiscal 2018 by $2,071.
Transition tax for accumulated foreign earnings, Income tax expense	$ 2,071	$ 24,641	$ 0

AVAILABLE-FOR-SALE-SECURITIES -

AVAILABLE-FOR-SALE-SECURITIES - FAIR VALUE AND GROSS REALIZED GAINS (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Sep. 30, 2017
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	$ 124,455	$ 0
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	124,501
Debt Securities, Available-for-sale, Unrealized Gain	8
Debt Securities, Available-for-sale, Unrealized Loss	(54)
Available-for-sale securities	124,455	$ 0
Asset-backed Securities [Member]
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	13,901
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	13,900
Debt Securities, Available-for-sale, Unrealized Gain	1
Debt Securities, Available-for-sale, Unrealized Loss	0
Available-for-sale securities	13,901
Certificates of Deposit [Member]
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	2,442
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,439
Debt Securities, Available-for-sale, Unrealized Gain	3
Debt Securities, Available-for-sale, Unrealized Loss	0
Available-for-sale securities	2,442
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	7,754
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	7,756
Debt Securities, Available-for-sale, Unrealized Gain	0
Debt Securities, Available-for-sale, Unrealized Loss	(2)
Available-for-sale securities	7,754
Corporate Debt Securities [Member]
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	75,260
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	75,312
Debt Securities, Available-for-sale, Unrealized Gain	0
Debt Securities, Available-for-sale, Unrealized Loss	(52)
Available-for-sale securities	75,260
US Treasury Securities [Member]
AVAILABLE FOR SALE SECURITIES [Abstract]
Available-for-sale securities	25,098
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	25,094
Debt Securities, Available-for-sale, Unrealized Gain	4
Debt Securities, Available-for-sale, Unrealized Loss	0
Available-for-sale securities	$ 25,098

AVAILABLE-FOR-SALE-SECURITIES,

AVAILABLE-FOR-SALE-SECURITIES, MATURITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$ 79,397
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	45,104
Available-for-sale Securities, Amortized Cost Basis	124,501
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	79,373
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	45,082
Available-for-sale securities	$ 124,455	$ 0

FAIR VALUE OF FINANCIAL INSTR40

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Assets [Abstract]
Available-for-sale securities	$ 124,455	$ 0
Asset-backed Securities [Member]
Assets [Abstract]
Available-for-sale securities	13,901
Certificates of Deposit [Member]
Assets [Abstract]
Available-for-sale securities	2,442
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets [Abstract]
Available-for-sale securities	7,754
Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale securities	75,260
US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale securities	25,098
Recurring [Member]
Assets [Abstract]
Cash and cash equivalents	186,124	397,890
Other long-term investments	1,089	929
Derivative financial instruments	8	263
Total assets	311,676	399,082
Liabilities [Abstract]
Derivative financial instruments	44	1,881
Total liabilities	44	1,881
Recurring [Member] \| Level 1 [Member]
Assets [Abstract]
Cash and cash equivalents	174,089	397,890
Other long-term investments	1,089	929
Derivative financial instruments	0	0
Total assets	175,178	398,819
Liabilities [Abstract]
Derivative financial instruments	0	0
Total liabilities	0	0
Recurring [Member] \| Level 2 [Member]
Assets [Abstract]
Cash and cash equivalents	12,035	0
Other long-term investments	0	0
Derivative financial instruments	8	263
Total assets	136,498	263
Liabilities [Abstract]
Derivative financial instruments	44	1,881
Total liabilities	44	1,881
Recurring [Member] \| Level 2 [Member] \| Asset-backed Securities [Member]
Assets [Abstract]
Available-for-sale securities	13,901
Recurring [Member] \| Level 2 [Member] \| Certificates of Deposit [Member]
Assets [Abstract]
Available-for-sale securities	2,442
Recurring [Member] \| Level 2 [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Assets [Abstract]
Available-for-sale securities	7,754
Recurring [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale securities	75,260
Recurring [Member] \| Level 2 [Member] \| US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale securities	25,098
Recurring [Member] \| Level 3 [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Other long-term investments	0	0
Derivative financial instruments	0	0
Total assets	0	0
Liabilities [Abstract]
Derivative financial instruments	0	0
Total liabilities	$ 0	$ 0

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
INVENTORIES [Abstract]
Raw materials	$ 40,255	$ 36,415
Work in process	8,036	7,365
Finished goods	29,011	28,093
Total	$ 77,302	$ 71,873

GOODWILL AND OTHER INTANGIBLE42

GOODWILL AND OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Goodwill [Roll Forward]
Balance, beginning of period					$ 101,932
Foreign exchange fluctuations					(178)
Decrease due to sale of surface finishes					(695)
Balance, end of period		$ 101,059			101,059
Sale of Productive Assets [Abstract]
(Gain) on sale of assets					(956)	$ 0
Finite-Lived Intangible Assets, Net [Abstract]
Total other intangible assets subject to amortization, gross carrying amount		85,154			85,154		$ 81,336
Accumulated amortization		49,342			49,342		43,816
Indefinite-lived Intangible Assets [Abstract]
Total other intangible assets not subject to amortization		1,170			1,170		5,190
Total other intangible assets, gross carrying amount		86,324			86,324		86,526
Other intangible assets [Abstract]
Amortization expense		1,780		$ 1,935	5,716	$ 5,860
Estimated future amortization expense [Abstract]
Remainder of 2018		1,780			1,780
2,019		7,119			7,119
2,020		7,115			7,115
2,021		7,108			7,108
2,022		7,108			7,108
Engineered Surface Finishes [Member]
Sale of Productive Assets [Abstract]
Net proceeds from sale of certain ESF			$ 3,277
Cash held in escrow			250
(Gain) on sale of assets			$ (956)
In-process Technology [Member]
Indefinite-lived Intangible Assets [Abstract]
Total other intangible assets not subject to amortization		0			0		4,000
Other Indefinite-lived Intangibles [Member]
Indefinite-lived Intangible Assets [Abstract]
Total other intangible assets not subject to amortization	[1]	1,170			1,170		1,190
Product Technology [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Total other intangible assets subject to amortization, gross carrying amount		46,273			46,273		42,287
Accumulated amortization		21,444			21,444		17,604
Acquired Patents and Licenses [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Total other intangible assets subject to amortization, gross carrying amount		8,270			8,270		8,270
Accumulated amortization		8,250			8,250		8,241
Trade Secrets and Know-how [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Total other intangible assets subject to amortization, gross carrying amount		2,550			2,550		2,550
Accumulated amortization		2,550			2,550		2,550
Customer Relationships, Distribution Rights and Other
Finite-Lived Intangible Assets, Net [Abstract]
Total other intangible assets subject to amortization, gross carrying amount		28,061			28,061		28,229
Accumulated amortization		$ 17,098			$ 17,098		$ 15,421

[1]	Other indefinite-lived intangible assets not subject to amortization consist primarily of trade names.

OTHER LONG-TERM ASSETS (Details

OTHER LONG-TERM ASSETS (Details) $ in Thousands	9 Months Ended
OTHER LONG-TERM ASSETS (Details) $ in Thousands	Jun. 30, 2018USD ($)Security	Sep. 30, 2017USD ($)	Jun. 30, 2015USD ($)
Other long-term assets [Abstract]
Auction rate securities (ARS)	$ 3,975	$ 5,319
Long-term contract assets	1,809	2,115
Other long-term assets	2,026	2,154
Other long-term investments	1,089	929
Total	$ 8,899	$ 10,517
Number of tax exempt municipal debt securities \| Security	1
Minimum maturity period of municipal debt securities	10 years
Fair value of auction rate securities	$ 3,975
Long-term contract asset face amount			$ 4,500
Amount of long-term contract paid	3,000
Long-term liability, SERP investments	$ 1,089

ACCRUED EXPENSES, INCOME TAXE44

ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
ACCRUED EXPENSES, INCOME TAXES PAYABLE AND OTHER CURRENT LIABILITIES [Abstract]
Accrued compensation	$ 30,205	$ 35,332
Income taxes payable	14,255	9,717
Dividends payable	10,687	5,314
Goods and services received, not yet invoiced	3,763	2,172
Deferred revenue and customer advances	3,296	1,559
Warranty accrual	220	247
Taxes, other than income taxes	2,213	1,688
Current portion of long-term contract liability	1,473	1,500
Other accrued expenses	5,897	5,122
Total	$ 72,009	$ 62,651

DEBT (Details)

DEBT (Details) - USD ($) $ in Thousands	Jun. 27, 2014	Jun. 26, 2014	Jun. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Feb. 13, 2012
Long-term Debt [Abstract]
Long-term debt, prepaid debt issuance cost			$ 0	$ 0		$ 441
Gain on termination of interest rate swaps			532
Current portion of long-term debt			$ 0	$ 0		10,938
Credit Agreement [Member] \| Revolving Credit Facility [Member]
Long-term Debt [Abstract]
Line of credit facility, borrowing capacity		$ 75,000
Maturity date of credit facility		Feb. 13, 2017
Credit Agreement [Member] \| Term Loan [Member]
Long-term Debt [Abstract]
Face amount of debt		$ 157,500					$ 175,000
Amended Credit Agreement [Member]
Long-term Debt [Abstract]
Interest rate description				borrowings under the amended Credit Facilities (other than in respect of swing-line loans) would bear interest at a rate per annum equal to the “Applicable Rate” (as defined below) plus, at our option, either (1) a LIBOR rate determined by reference to the cost of funds for deposits in the relevant currency for the interest period relevant to such borrowing or (2) the “Base Rate”, which is the highest of (x) the prime rate of Bank of America, N.A., (y) the federal funds rate plus 1/2 of 1.00% and (z) the one-month LIBOR rate plus 1.00%. The current Applicable Rate for borrowings under the amended Credit Facilities is 1.50%, with respect to LIBOR borrowings and 0.25% with respect to Base Rate borrowings, with such Applicable Rate subject to adjustment based on our consolidated leverage ratio. Swing-line loans bear interest at the Base Rate plus the Applicable Rate for Base Rate loans under the Revolving Credit Facility.
Covenant terms				The Credit Agreement contains covenants that restrict the ability of the Company and its subsidiaries to take certain actions, including, among other things and subject to certain significant exceptions: creating liens, incurring indebtedness, making investments, engaging in mergers, selling property, paying dividends or amending organizational documents. The Credit Agreement requires us to comply with certain financial ratio maintenance covenants. These include a maximum consolidated leverage ratio of 2.75 to 1.00 and a minimum consolidated fixed charge coverage ratio of 1.25 to 1.00 for the period January 1, 2016 through the expiration of the Credit Agreement. As of June 30, 2017, our consolidated leverage ratio was 0.00 to 1.00 and our consolidated fixed charge coverage ratio was 3.74 to 1.00. The Credit Agreement also contains customary affirmative covenants and events of default. We believe we are in compliance with these covenants.
Consolidated leverage ratio			0	0
Consolidated fixed charge coverage ratio			3.74	3.74
Amended Credit Agreement [Member] \| Minimum [Member]
Long-term Debt [Abstract]
Consolidated fixed charge coverage ratio			1.25	1.25
Amended Credit Agreement [Member] \| Maximum [Member]
Long-term Debt [Abstract]
Consolidated leverage ratio			2.75	2.75
Amended Credit Agreement [Member] \| Federal Funds Rate [Member]
Long-term Debt [Abstract]
Term of variable rate				1 month
Basis spread on variable rate				0.50%
Amended Credit Agreement [Member] \| LIBOR [Member]
Long-term Debt [Abstract]
Basis spread on variable rate				1.00%
Current applicable rate			1.50%	1.50%
Amended Credit Agreement [Member] \| Base Rate [Member]
Long-term Debt [Abstract]
Current applicable rate			0.25%	0.25%
Amended Credit Agreement [Member] \| Revolving Credit Facility [Member]
Long-term Debt [Abstract]
Line of credit facility, borrowing capacity			$ 100,000	$ 100,000
Maturity date of credit facility				Jun. 27, 2019
Interest rate description				In addition to paying interest on outstanding principal under the Credit Agreement, we pay a commitment fee to the lenders under the Revolving Credit Facility in respect of the unutilized commitments thereunder. As amended, the fee ranges from 0.20% to 0.30%, based on our consolidated leverage ratio.
Amended Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Long-term Debt [Abstract]
Commitment fee percentage				0.20%
Amended Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Long-term Debt [Abstract]
Commitment fee percentage				0.30%
Amended Credit Agreement [Member] \| Term Loan [Member]
Long-term Debt [Abstract]
Increase in loan commitments	$ 17,500
Amount drawn from increase in loan commitments	17,500
Term loan commitments outstanding	$ 175,000
Long-term debt, prepaid debt issuance cost					$ 315	$ 441

DERIVATIVE FINANCIAL INSTRUME46

DERIVATIVE FINANCIAL INSTRUMENTS (Details) ₩ in Thousands, $ in Thousands	Jun. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2017KRW (₩)	Dec. 31, 2014USD ($)
Interest Rate Swap [Member]
Derivative Instruments [Abstract]
Outstanding variable rate debt				$ 86,406
Foreign Exchange Contracts [Member] \| Buy [Member]
Derivative Instruments [Abstract]
Derivative notional amount	$ 7,907	$ 8,176
Foreign Exchange Contracts [Member] \| Sell [Member]
Derivative Instruments [Abstract]
Derivative notional amount	$ 20,825	$ 24,295
Net Investment Hedging [Member]
Derivative Instruments [Abstract]
Derivative notional amount \| ₩			₩ 100,000,000

DERIVATIVE FINANCIAL INSTRUME47

DERIVATIVE FINANCIAL INSTRUMENTS, SCHEDULE OF NET INVESTMENT HEDGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) $ in Thousands	9 Months Ended
	Jun. 30, 2018USD ($)
Derivatives used in Net Investment Hedge, Net of Tax [Roll Forward]
Balance, beginning of period	$ 920
Loss on net investment hedge	8,440
Tax benefit	(2,183)
Balance, end of period	$ 7,177

DERIVATIVE FINANCIAL INSTRUME48

DERIVATIVE FINANCIAL INSTRUMENTS, FAIR VALUE OF DERIVATIVE INSTRUMENTS IN THE CONSOLIDATED BALANCE SHEET (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member] \| Other Long-term Assets [Member]
Asset Derivatives [Abstract]
Fair value of foreign exchange contract asset derivatives	$ 0	$ 117
Liability Derivatives [Abstract]
Fair value of foreign exchange contract liability derivatives	0	0
Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member] \| Accrued Expenses and Other Current Liabilities [Member]
Asset Derivatives [Abstract]
Fair value of foreign exchange contract asset derivatives	0	0
Liability Derivatives [Abstract]
Fair value of foreign exchange contract liability derivatives	0	31
Designated as Hedging Instrument [Member] \| Net Investment Hedging [Member] \| Other Long-term Liabilities [Member]
Asset Derivatives [Abstract]
Fair value of foreign exchange contract asset derivatives	0	0
Liability Derivatives [Abstract]
Fair value of foreign exchange contract liability derivatives	0	1,442
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contracts [Member] \| Prepaid Expenses and Other Current Assets [Member]
Asset Derivatives [Abstract]
Fair value of foreign exchange contract asset derivatives	8	146
Liability Derivatives [Abstract]
Fair value of foreign exchange contract liability derivatives	0	0
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contracts [Member] \| Accrued Expenses and Other Current Liabilities [Member]
Asset Derivatives [Abstract]
Fair value of foreign exchange contract asset derivatives	0	0
Liability Derivatives [Abstract]
Fair value of foreign exchange contract liability derivatives	$ 44	$ 408

DERIVATIVE FINANCIAL INSTRUME49

DERIVATIVE FINANCIAL INSTRUMENTS, EFFECT OF DERIVATIVE INSTRUMENTS ON THE CONSOLIDATED STATEMENT OF INCOME (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Abstract]
Realized Gain	$ 532
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Abstract]
Realized Gain	532
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contracts [Member] \| Other Income, Net [Member]
Derivative Instruments, Gain (Loss) [Abstract]
Other income (loss), net	$ (1,080)	$ (235)	$ (1,002)	$ (1,709)

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Postretirement Obligations in Foreign Jurisdictions [Abstract]
Expected term for benefit payments of all unfunded plans	10 years
Expected future benefit payments	$ 5,785
Purchase obligations [Abstract]
Purchase obligation paid	1,500	$ 1,500
Purchase obligation, due in 2019	1,500
Contractual obligation	$ 1,502

ACCUMULATED OTHER COMPREHENSI51

ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			$ 595,037
Foreign currency translation adjustment, net of tax	$ (8,829)	$ (2,635)	2,276	$ (6,326)
Available-for-sale securities adjustments, net of tax	(48)	0	(48)	0
Change in fair value, net of tax			319	1,088
Reclassification adjustment into earnings, net of tax			(382)	(269)
Balance, end of period	634,181		634,181
Other Comprehensive Income, Tax [Abstract]
Foreign currency translation adjustment, tax			(2,303)	(1,814)
Available-for-sale securities adjustments, tax			0	0
Change in fair value, tax			111	610
Reclassification adjustment into earnings, tax			(133)	(150)
Change in pension and other postretirement liabilities, tax			0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			3,949	9,556
Balance, end of period	6,114	4,049	6,114	4,049
Foreign Currency Translation [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			5,239	11,985
Foreign currency translation adjustment, net of tax			2,276	(6,326)
Balance, end of period	7,515	5,659	7,515	5,659
Cash Flow Hedges [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			46	(817)
Change in fair value, net of tax			319	1,088
Reclassification adjustment into earnings, net of tax			(382)	(269)
Balance, end of period	(17)	2	(17)	2
Pension and Other Postretirement Liabilities [Member]
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			(1,336)	(1,612)
Balance, end of period	(1,336)	$ (1,612)	(1,336)	$ (1,612)
Available-For-Sale Securities
Components of Accumulated Comprehensive Income [Roll Forward]
Balance, beginning of period			0
Available-for-sale securities adjustments, net of tax			(48)
Balance, end of period	$ (48)		$ (48)

SHARE-BASED COMPENSATION PLAN52

SHARE-BASED COMPENSATION PLANS (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Total share-based compensation expense	$ 4,186		$ 3,251	$ 14,269	$ 9,716
Tax benefit	(1,023)		(1,052)	(3,272)	(3,219)
Total share-based compensation expense, net of tax	3,163		2,199	10,997	6,497
Share-based Compensation				14,269	9,716
Tax benefit from share-based compensation plans		$ (2,806)
Cost of Goods Sold [Member]
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Total share-based compensation expense	542		577	1,896	1,670
Research, Development and Technical [Member]
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Total share-based compensation expense	445		444	1,491	1,322
Selling and Marketing [Member]
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Total share-based compensation expense	290		346	961	1,032
General and Administrative [Member]
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Total share-based compensation expense	2,909		$ 1,884	$ 9,921	$ 5,692
Stock Option and Restricted Stock [Member]
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Vesting period of awards				4 years
Share-based Compensation	$ 858			$ 2,602

OTHER INCOME, NET (Details)

OTHER INCOME, NET (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
OTHER INCOME, NET (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
OTHER INCOME, NET [Abstract]
Interest income	$ 1,141	$ 659	$ 3,248	$ 1,596
Other income (expense)	486	(774)	113	(481)
Total other income (expense), net	$ 1,627	$ (115)	$ 3,361	$ 1,115

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2019	Sep. 30, 2018
Income Tax [Abstract]
Effective income tax rate	18.30%		22.40%	47.00%	21.10%
Federal statutory tax rate				21.00%
Transition tax on un-repatriated earnings of foreign subsidiaries payment period				8 years
Provisional discrete tax expense	$ (299)	$ 32,880
Transition tax for accumulated foreign earnings, Income tax expense		$ 2,071		$ 24,641	$ 0
Transition tax for accumulated foreign earnings, Liability, Noncurrent	$ 22,450			22,450
Provisional non-US withholding taxes				6,126
Discrete non-cash expense, change in tax rate				$ 1,813
Forecast [Member]
Income Tax [Abstract]
Federal statutory tax rate						21.00%	24.50%
Foreign Country [Member] \| South Korea [Member]
Income Tax Holiday [Abstract]
Percentage of local statutory rate in effect for 2017					50.00%
Percentage of local statutory rate in effect for 2016					50.00%
Percentage applicable on federal statutory tax rate - 2015					0.00%
Percentage applicable on federal statutory tax rate - 2014					0.00%
Percentage applicable on federal statutory tax rate - 2013					0.00%
Income tax provision reduction as a result of the tax holiday					$ 3,094
Tax Holiday approximate diluted earning per share benefit (in dollars per share)					$ 0.12

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator [Abstract]
Net income (loss)	$ 35,171	$ 19,939	$ 61,825	$ 60,450
Less: income attributable to participating securities	(34)	(52)	(73)	(191)
Earnings available to common shares	$ 35,137	$ 19,887	$ 61,752	$ 60,259
Denominator [Abstract]
Weighted average common shares (Denominator for basic calculation) (in shares)	25,611,505	25,228,468	25,479,078	24,941,190
Weighted average effect of dilutive securities [Abstract]
Share-based compensation (in shares)	707,133	492,247	742,786	508,317
Diluted weighted average common shares (Denominator for diluted calculation) (in shares)	26,318,638	25,720,715	26,221,864	25,449,507
Earnings per share [Abstract]
Basic (in dollars per share)	$ 1.37	$ 0.79	$ 2.42	$ 2.42
Diluted (in dollars per share)	$ 1.34	$ 0.77	$ 2.35	$ 2.37
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract]
Outstanding stock options excluded from diluted earnings (in shares)	100,000	100,000	100,000	400,000

FINANCIAL INFORMATION BY INDU56

FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Segment	Jun. 30, 2017USD ($)
FINANCIAL INFORMATION BY INDUSTRY SEGMENT AND PRODUCT LINE [Abstract]
Number of segments \| Segment			1
Revenue from External Customers by Products and Services [Abstract]
Revenue	$ 150,437	$ 127,957	$ 433,394	$ 370,395
Tungsten Slurries [Member]
Revenue from External Customers by Products and Services [Abstract]
Revenue	64,313	54,731	187,618	161,867
Dielectric Slurries [Member]
Revenue from External Customers by Products and Services [Abstract]
Revenue	36,616	30,266	102,877	87,391
Polishing Pads [Member]
Revenue from External Customers by Products and Services [Abstract]
Revenue	20,918	17,599	60,813	50,947
Other Metals Slurries [Member]
Revenue from External Customers by Products and Services [Abstract]
Revenue	18,124	16,090	51,476	46,540
ESF and Other [Member]
Revenue from External Customers by Products and Services [Abstract]
Revenue	$ 10,466	$ 9,271	$ 30,610	$ 23,650