Revenue from Contracts with Customers - Revenue From Contracts With Customers Table (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Product sales	$ 75,937
Total revenues and other	437,168	$ 516,193
Fee Based [Member]
Disaggregation of Revenue [Line Items]
Service revenues - fee and product based	338,419
Product Based [Member]
Disaggregation of Revenue [Line Items]
Service revenues - fee and product based	22,593
Customers [Member]
Disaggregation of Revenue [Line Items]
Product sales	77,180
Total revenue from customers	438,192
Customers [Member] | Fee Based [Member]
Disaggregation of Revenue [Line Items]
Service revenues - fee and product based	338,419
Customers [Member] | Product Based [Member]
Disaggregation of Revenue [Line Items]
Service revenues - fee and product based	22,593
Other Than Customers [Member]
Disaggregation of Revenue [Line Items]
Net gains (losses) on commodity price swap agreements	(1,243)
Other	$ 219