Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2017

Supplemental Cash Flow Information [Abstract]

Schedule of Cash Flow, Supplemental Disclosures

The supplemental cash flow information consists of the following (in thousands):

	Year Ended December 31,
	2017		2016		2015
Taxes paid	$	51,231	$	47,289	$	40,621
Non-cash investing activities:
Fixed assets acquired with accounts payable or accrued liabilities	$	15,105	$	4,434	$	14,636
Fair value of option to purchase property	$	3,936	$	—	$	—