Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Trade accounts receivable, allowance	$ 973	$ 1,190
Other, accumulated amortization of debt issuance costs	13,257	10,186
Intangible assets, accumulated amortization	59,492	44,856
Deferred revenues, related party amounts	52	41
Series A Preferred Units, redemption amount	$ 85,008	$ 84,773