Leases - Future Minimum Lease Payments for Lease Obligations (Details) $ in Millions	Dec. 31, 2015 USD ($)
Schedule Of Capital And Operating Leased Assets [Line Items]
Operating lease for land, Total	$ 1.2
Operating lease for land, 2016	0.5
Operating lease for land, 2017	0.5
Operating lease for land, 2018	0.2
Future minimum lease payments, Total	65.6
Future minimum lease payments, 2016	3.0
Future minimum lease payments, 2017	4.8
Future minimum lease payments, 2018	4.5
Future minimum lease payments, 2019	4.3
Future minimum lease payments, 2020	4.3
Future minimum lease payments, Remainder	44.7
Port Neches Storage Tanks
Schedule Of Capital And Operating Leased Assets [Line Items]
Capital lease for Port Neches storage tanks, Total	64.4	[1]
Capital lease for Port Neches storage tanks, 2016	2.5	[1]
Capital lease for Port Neches storage tanks, 2017	4.3	[1]
Capital lease for Port Neches storage tanks, 2018	4.3	[1]
Capital lease for Port Neches storage tanks, 2019	4.3	[1]
Capital lease for Port Neches storage tanks, 2020	4.3	[1]
Capital lease for Port Neches storage tanks, Remainder	$ 44.7	[1]

[1] Future minimum lease payments include $41.6 million in interest, $22.8 million in principal and excludes $11.3 million in executory costs.