Recent Accounting Pronouncements - Impact on Unaudited Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets [Abstract]
Accounts receivable, net	$ 109,764	$ 112,194
Total assets	549,269	499,060
Liabilities [Abstract]
Other current liabilities	44,172	38,077
Total liabilities	194,265	$ 132,709
ASC Topic 606 Impact | ASU 2014-09
Assets [Abstract]
Accounts receivable, net	(1,512)
Total assets	(1,512)
Liabilities [Abstract]
Other current liabilities	(1,512)
Total liabilities	(1,512)
Without ASC Topic 606 Adoption | ASU 2014-09
Assets [Abstract]
Accounts receivable, net	108,252
Total assets	547,757
Liabilities [Abstract]
Other current liabilities	42,660
Total liabilities	$ 192,753