Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013
Supplemental Cash Flow Information [Abstract]
Cash paid during the period for interest	$ 46,002		$ 41,315
Change in accrued capital expenditures	16,309		9,452
Amortization of increasing rate distributions	12,089	[1]	11,605	[1]
Recognition of deferred Class B unit obligations	$ 141,777

[1] Amortization of increasing rate distributions is offset in the preferred unitholders’ capital account by a non-cash distribution.