Segment Information - Revenues and Long-Lived Assets by Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 188,834	$ 181,621	$ 205,190	$ 212,724	$ 196,651	$ 188,117	$ 205,179	$ 210,345	$ 788,369	$ 800,292	$ 809,525
Long-lived assets	453,488				518,563				453,488	518,563	614,972
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									606,134	634,097	654,160
Long-lived assets	341,052				360,203				341,052	360,203	404,723
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									169,058	152,629	141,186
Long-lived assets	111,610				153,214				111,610	153,214	162,914
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									13,177	13,566	12,640
Long-lived assets	826				3,787				826	3,787	4,755
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									0	0	1,539
Long-lived assets	0				0				0	0	42,538
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 0				$ 1,359				$ 0	$ 1,359	$ 42