Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income (loss)	$ 102,861	$ 97,595
Income allocated to participating securities	172	216
Income available to common shareholders	$ 102,689	$ 97,379
Basic and diluted net income per share	$ 1.00	$ 0.96
Weighted Average Number of Shares Outstanding, Basic and Diluted	102,713,000	101,581,000
Earnings Per Share Diluted Other Disclosures Abstract
Share Repurchase Program - Shares Purchased	0	0

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

No definition available.

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- References

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=51831255

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831270

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-Name Regulation S-X (SX)
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- Definition

Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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- Definition

Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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- Definition

Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

+ References

No definition available.

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