Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Share data, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Statement of Financial Position [Abstract]    
Accounts receivable, allowance for doubtful accounts $ 5,571 $ 4,867
Property and equipment, accumulated depreciation 161,038 144,220
Other intangible assets, accumulated amortization $ 611,562 $ 574,503
Common stock issued (in shares) 208,012,259 207,493,541
Common stock outstanding (in shares) 208,012,259 207,493,541