Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Revenue recognition
Sales	$ 354,492	$ 368,609	$ 661,629	$ 683,405
Operating income (loss)	22,177	37,376	34,007	57,885
Depreciation and amortization	7,852	6,879	15,229	11,597
Transportation Systems
Revenue recognition
Sales	149,000	142,400	276,100	263,600
Operating income (loss)	16,800	35,300	19,900	50,500
Depreciation and amortization	3,200	1,000	5,800	1,500
Mission Support Services
Revenue recognition
Sales	100,700	122,200	199,900	235,600
Operating income (loss)	1,400	3,600	4,200	7,800
Depreciation and amortization	2,600	3,400	5,800	6,500
Defense Systems
Revenue recognition
Sales	104,800	103,900	185,600	183,900
Operating income (loss)	5,700		12,800	1,500
Depreciation and amortization	1,800	2,100	3,200	2,900
Other
Revenue recognition
Sales		100		300
Depreciation and amortization	200	400	400	700
Unallocated corporate expenses and other
Revenue recognition
Operating income (loss)	$ (1,700)	$ (1,500)	$ (2,900)	$ (1,900)