Debt (Tables)

3 Months Ended

Dec. 31, 2016

Debt

Schedule of components of unsecured long-term debt outstanding

	Principal				Unamortized Discount and Debt Issuance Costs
	December 31,		September 30,		December 31,			September 30,
	2016		2016		2016			2016
	(in thousands)
Unsecured senior notes issued March 19, 2015:
Due March 19, 2025	500,000		500,000		(7,890		)	(8,153		)
	500,000		500,000		(7,890		)	(8,153		)
Less long-term debt due within one year	—		—		—			—
Long-term debt	$	500,000	$	500,000	$	(7,890	)	$	(8,153	)