Supplemental Guarantor Information (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 20,430	$ 7,118
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,652)	(2,469)
Total other comprehensive income (loss)	(1,652)	(2,469)
Comprehensive income (loss)	18,778	4,649
Parent Company [Member]
Net income	20,430	7,118
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,652)	(2,469)
Total other comprehensive income (loss)	(1,652)	(2,469)
Comprehensive income (loss)	18,778	4,649
Guarantor Subsidiaries [Member]
Net income	24,279	26,119
Other comprehensive income (loss):
Foreign currency translation adjustment	0	0
Total other comprehensive income (loss)	0	0
Comprehensive income (loss)	24,279	26,119
Non-Guarantor Subsidiaries [Member]
Net income	(249)	540
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,652)	(2,469)
Total other comprehensive income (loss)	(1,652)	(2,469)
Comprehensive income (loss)	(1,901)	(1,929)
Eliminations and Other [Member]
Net income	(24,030)	(26,659)
Other comprehensive income (loss):
Foreign currency translation adjustment	1,652	2,469
Total other comprehensive income (loss)	1,652	2,469
Comprehensive income (loss)	$ (22,378)	$ (24,190)