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

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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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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.

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Long-Term Obligations and Notes Payable Reliant Bank Revolver (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Jun. 20, 2018 USD ($)	Mar. 30, 2018 USD ($)	Mar. 30, 2018 CAD ($)	Dec. 31, 2017 USD ($)	May 23, 2017 USD ($)
Debt Instrument [Line Items]
Long-term debt	$ 1,783,300,000				$ 1,465,600,000
Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 1,000,000,000.0	$ 50.0
Long-term debt	300,000,000.0				0
Unused credit commitments	$ 520,600,000
Revolving Credit Facility \| Line of Credit \| Reliant Bank Revolver
Debt Instrument [Line Items]
Interest rate, stated percentage		4.75%				5.25%
Line of credit facility, maximum borrowing capacity		$ 30,000,000.0				$ 17,000,000.0
Unused capacity, commitment fee percentage	0.50%
Long-term debt	$ 30,000,000.0				$ 17,000,000.0
Unused credit commitments	$ 0