Basis of Presentation and Nature of Operations - Schedule of Contract Assets and Contract Liabilities Reported under New Accounting Standard (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Contract receivables, net	$ 194,202	$ 168,318
Contract assets	143,161	123,197
Contract liabilities	26,489	38,571
Retained earnings	470,386	434,766
ASU 2014-09 \| As Reported
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Contract receivables, net		291,515
Contract assets	141,391	123,197
Deferred revenue		38,571
Contract liabilities	$ 27,009	38,571
Retained earnings		$ 434,766

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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