Leases (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) mi	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating Leases [Line Items]
Total rent expense | $	$ 25.7	$ 21.0	$ 12.0
Minimum [Member]
Operating Leases [Line Items]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	1 year
Maximum [Member]
Operating Leases [Line Items]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	20 years
Texas and New Mexico Pipeline (Leased) [Member]
Operating Leases [Line Items]
Pipeline, Length | mi	40