Investments in Non-Consolidated Subsidiaries Investments in Non-Consolidated Subsidiaries (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Proceeds from Equity Method Investment, Dividends or Distributions			$ 39,714	$ 25,053
White Cliffs Pipeline L L C [Member]
Proceeds from Equity Method Investment, Dividends or Distributions	12,755	10,794	39,436	30,561
NGL Energy Partners LP [Member]
Proceeds from Equity Method Investment, Dividends or Distributions	4,671	2,090	13,369	5,063
Glass Mountain Pipeline Llc [Member]
Proceeds from Equity Method Investment, Dividends or Distributions	0	0	0	0
Return of and return on capital [Member]
Proceeds from Equity Method Investment, Dividends or Distributions	$ 17,426	$ 12,884	$ 52,805	$ 35,624