Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Narrative (Details)

Shareholders' Equity - Narrative (Details) (USD $)
In Millions, except Share data in Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2015
Mar. 31, 2014
Class of Stock [Line Items]      
Cash dividends paid on common stock   $ 25.2us-gaap_PaymentsOfDividendsCommonStock $ 24.8us-gaap_PaymentsOfDividendsCommonStock
Shares repurchased   305us-gaap_TreasuryStockSharesAcquired  
Amount of shares repurchased   $ 9.2us-gaap_PaymentsForRepurchaseOfCommonStock $ 16.5us-gaap_PaymentsForRepurchaseOfCommonStock
Common stock, shares issued 245us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation    
Treasury Stock      
Class of Stock [Line Items]      
Common stock, shares issued 317us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_TreasuryStockMember