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Debt - Additional Information (Details)		3 Months Ended
	Aug. 09, 2019 USD ($) $ / shares	Sep. 30, 2019	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)
Senior bank debt | Revolver
Debt Instrument [Line Items]
Total available borrowing				$ 1,250,000,000
Additional borrowing amount				500,000,000.0
Senior bank debt | Revolver | LIBOR
Debt Instrument [Line Items]
Basis spread on debt variable rate		1.10%
Senior bank debt | Term Loan
Debt Instrument [Line Items]
Total available borrowing				450,000,000.0
Additional borrowing amount				$ 75,000,000.0
Senior bank debt | Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread on debt variable rate		0.875%
Junior convertible securities | 5.15% Junior Convertible Trust Preferred Securities
Debt Instrument [Line Items]
Debt interest rate		5.15%
Conversion ratio per share of common stock	0.2558
Face amount of convertible security	$ 50.00
Adjusted conversion price (in dollars per share) | $ / shares	$ 195.47
Junior subordinated notes | 5.875% Junior Subordinated Notes due 2059
Debt Instrument [Line Items]
Debt interest rate				5.875%
Debt issued			$ 300,000,000.0	$ 280,000,000.0
Additional debt issued			$ 20,000,000.0
Debt redemption price percentage of principal amount				100.00%
Debt redemption price percentage of principal amount plus unpaid and accrued interest				102.00%
Junior subordinated notes | 5.875% Junior Subordinated Notes due 2059 | On or after March 30, 2024
Debt Instrument [Line Items]
Debt redemption price percentage of principal amount				100.00%
Junior subordinated notes | 5.875% Junior Subordinated Notes due 2059 | Prior to March 30, 2024
Debt Instrument [Line Items]
Debt redemption price percentage of principal amount				100.00%

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Debt Instrument, Individual Security, Face Amount

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Debt Instrument, Redemption Price, Plus Accrued and Unpaid Interest, Percentage

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Line of Credit Facility, Maximum Borrowing Capacity, Additional Amount

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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

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

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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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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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