CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash Flows from Operating Activities:
Net income	$ 43,866	$ 45,099
Adjustments to reconcile net income to net cash provided by operations:
Depreciation	34,401	32,979
Amortization	1,486	1,081
Stock based compensation	10,104	9,530
Provision for (recovery of) doubtful accounts	13	(156)
Deferred income taxes	(867)	(1,001)
Defined benefit plan expense	4,194	5,161
Equity in results of affiliates	121	119
Changes in balance sheet items, excluding effects from foreign currency adjustments:
Accounts receivables	(70,863)	(44,798)
Inventories	(1,792)	1,040
Prepaid and other current assets	(14,646)	(12,975)
Accounts payable and accrued liabilities	11,362	12,691
Income taxes payable	(737)	(2,879)
Retirement and deferred compensation plan liabilities	(15,151)	(4,567)
Other changes, net	10,386	(1,558)
Net Cash Provided by Operations	11,877	39,766
Cash Flows from Investing Activities:
Capital expenditures	(24,218)	(26,885)
Proceeds from sale of property and equipment, including insurance proceeds	1,234	1,840
Maturity of short-term investments	29,485
Acquisition of business, net of cash acquired	(202,985)
Acquisition of ntangible assets	(2,514)
Notes receivable, net	319	151
Net Cash Used by Investing Activities	(198,679)	(24,894)
Cash Flows from Financing Activities:
Proceeds from (repayments of) notes payable	75,180	(229,294)
Proceeds from long-term obligations	101	225,000
Repayments of long-term obligations	(1,047)	(755)
Dividends paid	(18,770)	(17,402)
Credit facility costs		(399)
Proceeds from stock option exercises	20,960	19,671
Common stock repurchased and retired	(8,641)
Excess tax benefit from exercise of stock options	3,764	3,421
Net Cash Provided by Financing Activities	71,547	242
Effect of Exchange Rate Changes on Cash	11,326	(29,183)
Net decrease in Cash and Equivalents	(103,929)	(14,069)
Cash and Equivalents at Beginning of Period	489,901	399,762
Cash and Equivalents at End of Period	$ 385,972	$ 385,693