Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Revenue recognition
Sales	$ 364,305	$ 339,645	$ 677,676	$ 656,411
Operating income (loss)	34,648	32,540	52,890	60,294
Depreciation and amortization	6,879	5,465	11,597	11,297
Transportation Systems
Revenue recognition
Sales	138,800	131,700	257,400	257,500
Operating income (loss)	32,200	23,400	45,400	41,300
Depreciation and amortization	1,000	800	1,500	1,700
Mission Support Services
Revenue recognition
Sales	122,200	126,900	235,600	234,400
Operating income (loss)	3,600	4,600	7,800	9,100
Depreciation and amortization	3,400	3,000	6,500	6,500
Defense Systems
Revenue recognition
Sales	103,200	80,700	184,400	164,000
Operating income (loss)	300	6,100	1,500	12,100
Depreciation and amortization	2,100	1,300	2,900	2,500
Other
Revenue recognition
Sales	100	300	300	500
Depreciation and amortization	400	400	700	600
Unallocated corporate expenses and other
Revenue recognition
Operating income (loss)	$ (1,500)	$ (1,600)	$ (1,800)	$ (2,200)