Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract assets	$ 22,322	$ 23,040
Dollar change in contract assets	(718)
Contract liabilities	3,418	$ 4,537
Dollar change in contract liabilities	$ (1,119)

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.

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-Publisher FASB
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Balance Type:	debit
Period Type:	instant

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of increase (decrease) in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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- Definition

Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable.

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