Debt (Summary of notes carrying value) (Detail 1) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018	Nov. 30, 2015
Debt Instrument [Line Items]
Principal amount			$ 143,750
Net carrying value	$ 317,121	$ 317,398
Convertible Senior Notes, net
Debt Instrument [Line Items]
Principal amount	143,750	143,750
Unamortized debt discount	(11,104)	(13,909)
Unamortized debt issuance costs	(1,566)	(1,984)
Net carrying value	$ 131,080	$ 127,857

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount, after accumulated amortization, of debt discount.

+ References

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-Publisher FASB
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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