Debt Obligations - Long-term Debt Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Borrowings under credit facility	$ 668,427	$ 351,341
Other long-term debt, interest rates ranging from 2.4% to 4.3%	1,810	3,305
Capital leases, interest rates ranging from 2.5% to 3.8%	1,704	3,744
Total long-term debt obligations	671,941	358,390
Less — Current maturities of long-term debt	1,220	4,828
Total long-term debt obligations, net of current maturities	$ 670,721	$ 353,562
Other Long Term Debt \| Minimum
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	2.40%	2.40%
Other Long Term Debt \| Maximum
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	4.30%	4.30%
Capital Lease Obligations \| Minimum
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	2.50%	2.50%
Capital Lease Obligations \| Maximum
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	3.80%	3.80%

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Contractual interest rate for funds borrowed, under the debt agreement.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt classified as other.

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