Geographic Information (Schedule of Revenues from External Customers by Geographical Areas) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 647,814	$ 640,867	$ 690,741
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	365,085	374,453	388,977
Canada
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	137,684	113,391	92,656
Middle East and Africa
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	84,330	61,618	79,778
Europe (including former Soviet Union)
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	34,920	24,092	24,857
Far East
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	15,127	35,388	12,418
Mexico, Central and South America
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 10,668	$ 31,925	$ 92,055