Receivables and Other Current Assets - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, less allowance for doubtful accounts of $6,800	$ 256,560	$ 124,659
Other receivables and current assets	181,001	263,820
Balance at January 1st after ASC 606 Adoption
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, less allowance for doubtful accounts of $6,800		278,800
Deferred Accounts Receivable Current Portion Of Lease Licenses And Software Maintenance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables and current assets	$ 134,613	215,155
Deferred Accounts Receivable Current Portion Of Lease Licenses And Software Maintenance [Member] | Balance at January 1st after ASC 606 Adoption
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables and current assets		$ 136,400