Condensed Consolidated Balance Sheets Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$ 291	$ 266
Finite-Lived Intangible Assets, Accumulated Amortization	$ 155,017	$ 147,322
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	325,000,000	325,000,000
Common Stock, Shares, Issued	92,565,682	91,845,492
Common Stock, Shares, Outstanding	85,614,964	86,770,737
Treasury Stock, Shares	6,950,718	5,074,755