CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
CONDENSED CONSOLIDATED BALANCE SHEETS
Trade accounts receivable from related parties	$ 212	$ 368
Trade accounts receivable, allowance for doubtful accounts (in dollars)	1,297	483
Prepayments to related parties	5,023	3,012
Accounts payable to related parties	1,584
Accrued liabilities to related parties	462	115
Deferred revenue from related parties		$ 61
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	175,772,173	175,772,173
Common stock, shares issued	158,210,719	158,210,719
Common stock held in treasury, at cost	2,448,553	2,500,000