Share Repurchase Program and Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Share Repurchase Program and Treasury Stock (Textuals) [Abstract]
Authorized amount under share repurchase program	$ 860,000
Shares Purchased Under Share Repurchase Program	26,300,000
Repurchases of common stock	$ (124,997)		$ (499,992)
Number of shares repurchased	(275,088)	(390,337)
Average price of share repurchased, per share	$ 454.37	$ 320.22
Exercise of stock options and restricted stock units, shares reissued	76,849	59,321