Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130533-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

Name:	us-gaap_ContractWithCustomerAssetNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Revenue (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Revenue (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Contract assets	$ 148,205		$ 142,779
Advance payments from customers	76,833		84,122
Customer Deposits and Prepayments of Inventory [Member]
Disaggregation Of Revenue [Line Items]
Advance payments from customers	50,700		54,900
Contractual Timing of Payments [Member]
Disaggregation Of Revenue [Line Items]
Advance payments from customers	$ 26,100		$ 29,200
Transferred Over Time [Member]
Disaggregation Of Revenue [Line Items]
Percentage Of Revenue	90.00%	90.00%