COMMON STOCK EQUITY (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)	42,178,156us-gaap_CommonStockSharesOutstanding
Balance as of beginning of period	$ 966,166us-gaap_StockholdersEquity
Net income	123,320us-gaap_NetIncomeLoss	7,693us-gaap_NetIncomeLoss
Other comprehensive income	875	(183)
Common stock issued under stock plans	29,403
Tax benefits from stock plans	(1,409)
Cash dividend declared ($.45 per share)	(19,023)us-gaap_DividendsCash
Treasury stock and other	4,314
Balance as of end of period (shares)	42,651,486us-gaap_CommonStockSharesOutstanding
Balance as of end of period	1,103,646us-gaap_StockholdersEquity
Cash dividend declared per share (usd per share)	$ 0.45	$ 0.42
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)	42,178,000
Balance as of beginning of period	112,777
Common stock issued under stock plans (shares)	564,000
Common stock issued under stock plans	1,258
Treasury stock and other (shares)	(91,000)
Balance as of end of period (shares)	42,651,000
Balance as of end of period	114,035
Premium on Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period	305,185
Common stock issued under stock plans	25,099
Tax benefits from stock plans	(1,409)
Balance as of end of period	328,875
Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period	(5,594)
Other comprehensive income	875
Balance as of end of period	(4,719)
Treasury Stock And Other [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period	(121,031)
Common stock issued under stock plans	3,046
Treasury Stock and Other, Value, Acquired, Cost Method	(4,314)
Balance as of end of period	(113,671)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period	674,829
Net income	123,320
Cash dividend declared ($.45 per share)	(19,023)
Balance as of end of period	$ 779,126

Stock Issued During Period, Shares, Dividend Reinvestment Plan, Treasury Stock Reissued and Share-based Compensation

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Stock Issued During Period, Value, Dividend Reinvestment Plan, Treasury Stock Reissued and Share-based Compensation

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Treasury Stock and Other, Value, Acquired, Cost Method

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Amount of increase in additional paid in capital (APIC) resulting from a tax benefit associated with share-based compensation plan other than an employee stock ownership plan (ESOP). Includes, but is not limited to, excess tax benefit.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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