Debt (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Carrying Amounts and Estimated Fair Value of Long-Term Debt

Carrying amounts and the related estimated fair values of the Company’s long-term debt financial instruments not measured at fair value on a recurring basis at September 30, 2018 and December 31, 2017 are presented in the following table:

	As of September 30, 2018						As of December 31, 2017
$ in millions	Principal		Carrying Amount		Fair Value		Principal		Carrying Amount		Fair Value
Total long-term debt including current portion	$	300.0	$	294.0	$	309.0	$	300.8	$	294.3	$	312.7