Indebtedness (Details 1) - Senior Secured Credit Facilities	9 Months Ended
	Sep. 30, 2018
Term A loan
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	3.99%
Term A-1 loan
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	3.99%
Term B-3 loan
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	4.49%
LIBOR | Term A loan
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
LIBOR | Term A-1 loan
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
LIBOR | Term B-3 loan
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.25%
LIBOR | Revolver
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%	[1]

[1] Includes unused commitment fee of 0.30% and letter of credit fee of 1.75% not reflected in interest rate above.