Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance for doubtful accounts	$ 9,248	$ 6,728
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	296,753,544	296,564,382
Common stock, shares outstanding	296,753,544	296,564,382