Long-Term Obligations and Notes Payable - Reliant Bank Revolver (Details) $ in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)	Jun. 20, 2018 USD ($)	Mar. 30, 2018 USD ($)	Mar. 30, 2018 CAD ($)	Dec. 31, 2017 USD ($)	May 23, 2017 USD ($)
Line of Credit Facility [Line Items]
Long-term Debt	$ 1,862.0				$ 1,465.6
Line of credit | Revolving credit facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 1,000.0	$ 50.0
Long-term Debt	300.0
Remaining borrowing capacity	$ 556.5
Line of credit | Reliant Bank Revolver | Revolving credit facility
Line of Credit Facility [Line Items]
Stated interest rate (as percent)		4.75%				5.25%
Maximum borrowing capacity		$ 30.0				$ 17.0
Commitment fee percentage (as percent)	0.50%
Long-term Debt	$ 30.0				$ 17.0
Remaining borrowing capacity	$ 0.0