Share Repurchase Program and Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Share Repurchase Program and Treasury Stock (Textuals) [Abstract]
Remaining Amount to Repurchase under the program	$ 230,900
Shares Purchased Under Share Repurchase Program	23,900,000
Treasury Stock, Value, Acquired, Cost Method	$ 247,473	$ 184,000	$ 414,000
Number of shares repurchased	777,248	757,374
Average price of share repurchased, per share	$ 318.38	$ 242.89
Exercise of stock options and restricted stock units, shares reissued	233,593	157,857