Debt - Debt Terms (Details) - SunTrust Bank		12 Months Ended
	May 04, 2017	Dec. 31, 2018	Sep. 30, 2018
Minimum
Debt Instrument [Line Items]
Applicable Margin		1.75%
Sun Trust Revolving Credit Facility | Leverage Ratio I
Debt Instrument [Line Items]
Leverage Ratio	1.25		1.25
Applicable Percentage For Commitment Fee	0.25%
Sun Trust Revolving Credit Facility | Leverage Ratio I | LIBOR
Debt Instrument [Line Items]
Applicable Margin	2.25%
Sun Trust Revolving Credit Facility | Leverage Ratio I | Base Rate
Debt Instrument [Line Items]
Applicable Margin	1.25%
Sun Trust Revolving Credit Facility | Leverage Ratio II
Debt Instrument [Line Items]
Applicable Percentage For Commitment Fee	0.375%
Sun Trust Revolving Credit Facility | Leverage Ratio II | Minimum
Debt Instrument [Line Items]
Leverage Ratio	1.25
Sun Trust Revolving Credit Facility | Leverage Ratio II | Maximum
Debt Instrument [Line Items]
Leverage Ratio	1.75
Sun Trust Revolving Credit Facility | Leverage Ratio II | LIBOR
Debt Instrument [Line Items]
Applicable Margin	2.50%
Sun Trust Revolving Credit Facility | Leverage Ratio II | Base Rate
Debt Instrument [Line Items]
Applicable Margin	1.50%
Sun Trust Revolving Credit Facility | Leverage Ratio III
Debt Instrument [Line Items]
Leverage Ratio	1.75
Applicable Percentage For Commitment Fee	0.375%
Sun Trust Revolving Credit Facility | Leverage Ratio III | LIBOR
Debt Instrument [Line Items]
Applicable Margin	2.75%
Sun Trust Revolving Credit Facility | Leverage Ratio III | Base Rate
Debt Instrument [Line Items]
Applicable Margin	1.75%