Share Repurchase Program (Tables)

6 Months Ended

Jun. 30, 2019

Proceeds from (Repurchase of) Equity [Abstract]

Schedule of shares repurchased

	For the Three Months Ended   June 30,				For the Six Months Ended   June 30,
	2019		2018		2019		2018
Shares repurchased	1,633		1,575		2,560		3,763
Average price per share	$	366.76	$	264.38	$	359.63	$	256.64
Total investment	$	598,846	$	416,402	$	920,692	$	965,830