Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Consolidated Balance Sheets
Net of allowance on accounts receivable	$ 27,862	$ 22,379
Preferred stock, par value
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value
Common stock, shares authorized	70,000	70,000
Common stock, shares outstanding	32,353	31,941