Share Repurchase Program (Tables)

9 Months Ended

Sep. 30, 2015

Proceeds from (Repurchase of) Equity [Abstract]

Schedule of shares repurchased

	For the Three Months Ended   September 30,				For the Nine Months Ended   September 30,
	2015		2014		2015		2014
Shares repurchased	1,147		2,542		3,784		4,564
Average price per share	$	238.97	$	152.42	$	224.39	$	150.55
Total investment	$	274,213	$	387,461	$	849,145	$	687,086