Balance Sheet Parenthetical (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts Receivable	$ 22,760	$ 22,079
Accumulated depreciation of property and equipment	240,215	231,327
Accumulated amortization of intangible assets	137,917	132,927
Accumulated amortization of other assets	$ 26,659	$ 25,363
Preferred Stock, par value per share	$ 0.02	$ 0.02
Preferred Stock, shares authorized	10,000,000	10,000,000
Preferred Stock, shares issued	0	0
Common Stock, par value per share	$ 0.02	$ 0.02
Common Stock, shares authorized	90,000,000	90,000,000
Common Stock, shares issued	54,612,164	54,276,761
Treasury Stock, shares	3,664,779	3,650,519