Income Taxes, Deferred Tax Asset Valuation Adjustments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Valuation Allowance [Roll Forward]
Recognition of valuation allowance on foreign tax credit carryforwards				$ 9,800		$ 27,200
Deferred Tax Asset Valuation Allowance [Member]
Valuation Allowance [Roll Forward]
Beginning balance		$ 77,042		68,697		56,906
Additions charged to cost and expenses		2,154	[1]	10,913	[2]	27,902	[3]
Decreases		(12,100)	[4]	(3,343)	[5]	(16,215)	[6]
Adjustments	[7]	244		775		104
Ending balance		$ 67,340		$ 77,042		$ 68,697

[1] Increase in valuation is due primarily to net operating losses in foreign markets.

[2] Increase in valuation is due primarily to $9.8 million that was recorded on the foreign tax credit carryforward. The additional amount is due to net operating losses in foreign markets.

[3] Increase in valuation is due primarily to the $27.2 million that was recorded on the foreign tax credit carryforward. The additional amount is due to net operating losses in foreign markets

[4] The decrease was due to the utilization of prior year foreign tax credits that had previously had a valuation allowance recorded against the asset.

[5] The decrease was due primarily to the utilization of foreign tax credits, and expiration of foreign net operating losses.

[6] The decrease was due primarily to the utilization of foreign tax credits. Decrease is due primarily to the write-off of Brazil deferred tax assets, which had no impact to the income statement, as a valuation allowance had been previously recorded against the asset.

[7] Represents the net currency effects of translating valuation allowances at current rates of exchange.