Share Repurchase Program (Tables)

6 Months Ended

Jun. 30, 2015

Proceeds from (Repurchase of) Equity [Abstract]

Schedule of shares repurchased

	For the Three Months Ended   June 30,				For the Six Months Ended   June 30,
	2015		2014		2015		2014
Shares repurchased	1,987		1,873		2,637		2,022
Average price per share	$	221.50	$	148.21	$	218.05	$	148.21
Total investment	$	440,129	$	277,561	$	574,932	$	299,625