Balance Sheet Parenthetical (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Allowance for doubtful accounts receivable	$ 20,139	$ 20,546
Accumulated depreciation of property and equipment	240,057	239,607
Accumulated amortization of intangible assets	126,039	113,153
Accumulated amortization of other assets	$ 36,159	$ 30,276
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	57,707,721	56,464,187
Treasury Stock, shares	4,928,927	4,867,420