Condensed Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 39,081	$ 46,218
Derivative financial instruments:
Unrealized holding gains/(losses)	(168)	1,065
Gains/(losses) reclassified to net income	694	(40)
Total other comprehensive income	526	1,025
Comprehensive income	$ 39,607	$ 47,243