Cap price of capped call transaction.

No definition available.

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- Definition

Debt instrument convertible conversion price percentage.

+ References

No definition available.

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- Definition

The amount of equity issuance cost.

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Payments for capped call transactions and associated costs.

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Percentage of principal amount of convertible notes is equal to repurchase price.

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No definition available.

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The amount of discount and estimated offering expenses.

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No definition available.

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Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Amount of debt discount to be amortized after one year or the normal operating cycle, if longer.

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Amount, before accumulated amortization, of debt issuance costs classified as current. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Fair value portion of notes payable.

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The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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Long-Term Debt (Narrative) (Details)			3 Months Ended		9 Months Ended
Long-Term Debt (Narrative) (Details)	May 14, 2019 USD ($) $ / shares	Jul. 06, 2016 USD ($) $ / shares	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) item	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2016 $ / shares
Proceeds from convertible debt					$ 223,424,000
Payments for capped call transactions and associated costs		$ 38,400,000
Cap price of capped call transaction \| $ / shares								$ 262.2725
Long-term debt			$ 525,339,000		525,339,000		$ 371,250,000
Interest expense			11,795,000	$ 7,671,000	29,518,000	$ 22,769,000
Convertible Debt [Member]
Debt issuance costs		19,000,000.0
Convertible debt, outstanding			$ 690,000,000.0		$ 690,000,000.0
Convertible Senior Notes 3.25% [Member] \| Convertible Debt [Member]
Debt instrument, face amount		460,000,000.0
Debt instrument, interest rate, stated percentage			3.25%		3.25%
Proceeds from convertible debt		447,600,000
Debt issuance costs		$ 12,400,000	$ 13,800,000		$ 13,800,000
Debt instrument convertible, percentage of conversion price			130.00%		130.00%
Average percentage of closing sale price of common stock					98.00%
Debt instrument, convertible, conversion ratio		5.0358
Debt instrument, convertible, conversion price \| $ / shares		$ 198.58
Percentage of repurchase price is equal to principal amount of convertible notes					100.00%
Debt instrument liability component effective interest rate			8.40%		8.40%
Long-term debt			$ 334,400,000		$ 334,400,000
Debt instrument, unamortized discount, noncurrent			113,100,000		113,100,000
Interest expense			11,800,000	$ 7,700,000	29,500,000	$ 22,800,000
Interest payable, current			5,500,000		5,500,000		7,500,000
Convertible debt, outstanding			460,000,000.0		460,000,000.0
Fair value of the Convertible Notes			$ 400,700,000		$ 400,700,000		$ 410,900,000
Convertible Senior Notes 3.25% [Member] \| Convertible Debt [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Maximum [Member]
Debt instrument convertible consecutive trading days					30
Convertible Senior Notes 3.25% [Member] \| Convertible Debt [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Minimum [Member]
Debt instrument convertible consecutive trading days					20
Convertible Senior Notes 3.25% [Member] \| Convertible Debt [Member] \| Ninety Eight Percent Applicable Conversion Price [Member]
Debt instrument convertible consecutive trading days \| item					5
Convertible Senior Notes 2.00% Due 2026 [Member] \| Convertible Debt [Member]
Debt instrument, face amount	$ 230,000,000.0
Debt instrument, interest rate, stated percentage			2.00%		2.00%
Proceeds from convertible debt	223,400,000
Debt issuance costs	$ 6,600,000
Debt instrument convertible, percentage of conversion price			130.00%		130.00%
Average percentage of closing sale price of common stock					98.00%
Debt instrument, convertible, conversion ratio	9.2123
Debt instrument, convertible, conversion price \| $ / shares	$ 108.55
Percentage of repurchase price is equal to principal amount of convertible notes					100.00%
Debt instrument liability component effective interest rate			9.90%		9.90%
Long-term debt			$ 137,500,000		$ 137,500,000
Debt instrument, unamortized discount, noncurrent			85,900,000		85,900,000
Convertible debt, outstanding			230,000,000.0		230,000,000.0
Underwriting discounts and estimated offering expenses			6,600,000		6,600,000
Equity issuance cost			2,500,000		2,500,000
Debt issuance costs			4,100,000		4,100,000
Fair value of the Convertible Notes			$ 213,900,000		$ 213,900,000
Convertible Senior Notes 2.00% Due 2026 [Member] \| Convertible Debt [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Maximum [Member]
Debt instrument convertible consecutive trading days					30
Convertible Senior Notes 2.00% Due 2026 [Member] \| Convertible Debt [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Minimum [Member]
Debt instrument convertible consecutive trading days					20
Convertible Senior Notes 2.00% Due 2026 [Member] \| Convertible Debt [Member] \| Ninety Eight Percent Applicable Conversion Price [Member]
Debt instrument convertible consecutive trading days \| item					5