Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,433	78,166	126,787
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit		$ 36.70	$ 35.69
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit		$ 37.98	$ 45.81
Accumulated other comprehensive loss, net of tax	$ (19,186,000)	$ (16,656,000)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(22,300,000)	(20,600,000)
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ 3,100,000	$ 3,900,000
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 37.54
Maximum [Member] | Building [Member]
Property, Plant and Equipment, Useful Life	40 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	10 years
Maximum [Member] | Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life	10 years
Minimum [Member] | Building [Member]
Property, Plant and Equipment, Useful Life	10 years
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	3 years
Minimum [Member] | Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life	3 years
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	135,000	156,000	175,000
Usg [Member]
Percentage of segment revenue from software components	100.00%
Percentage of consolidated revenue from software components	22.00%
Filtration [Member]
Percentage of segment revenues recognized when services are performed for unaffiliated customers or when products are delivered	85.00%
Percentage of consolidated revenues recognized when services are performed for unaffiliated customers or when products are delivered	37.00%
Percentage of segment revenues recorded under percentage of completion method	15.00%
Percentage of consolidated revenues recorded under percentage of completion method	7.00%
Test [Member]
Percentage of segment revenues recognized when services are performed for unaffiliated customers or when products are delivered	40.00%
Percentage of consolidated revenues recognized when services are performed for unaffiliated customers or when products are delivered	14.00%
Percentage of segment revenues recorded under percentage of completion method	60.00%
Percentage of consolidated revenues recorded under percentage of completion method	20.00%
Percentage of segment revenues for which reliable measure of output cannot be established for recognition	2.00%
Percentage of consolidated revenues for which reliable measure of output cannot be established for recognition	1.00%