Consolidated Statements of Comprehensive Income (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Actuarially Determined Long-Term Liability Adjustments, Tax	$ 1,164	$ 1,214
Unrealized gain (Loss) on Cash Flow Hedges, Tax	$ (144)	$ (933)

Amount of tax expense (benefit) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e640-108580

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration