Summary of Assets and Liabilities Recorded at Fair Value on Recurring Basis (Detail) - Recurring - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Assets, fair value	$ 205,220	$ 213,370
Liabilities:
Liabilities, fair value	32,773	32,998
Money Market Mutual Funds | Other Assets
Assets:
Assets, fair value	110,830	106,530
Certificates of Deposit | Other Assets
Assets:
Assets, fair value	2,202	5,415
Available for Sale Securities | Other Assets
Assets:
Assets, fair value	58,213	55,594
Deferred Compensation Assets | Other Assets
Assets:
Assets, fair value	32,773	32,998
Interest Rate Swap Agreements | Accounts Receivable, Net
Assets:
Assets, fair value		3,925
Foreign Currency Foreign Exchange Contracts | Other Current Assets
Assets:
Assets, fair value		8,908
Offsetting of assets, fair value	1,202
Deferred Compensation Liability | Other Noncurrent Liabilities
Liabilities:
Liabilities, fair value	32,773	32,998
Basis of Fair Value Measurement, Level 1
Assets:
Assets, fair value	204,018	200,537
Liabilities:
Liabilities, fair value	32,773	32,998
Basis of Fair Value Measurement, Level 1 | Money Market Mutual Funds | Other Assets
Assets:
Assets, fair value	110,830	106,530
Basis of Fair Value Measurement, Level 1 | Certificates of Deposit | Other Assets
Assets:
Assets, fair value	2,202	5,415
Basis of Fair Value Measurement, Level 1 | Available for Sale Securities | Other Assets
Assets:
Assets, fair value	58,213	55,594
Basis of Fair Value Measurement, Level 1 | Deferred Compensation Assets | Other Assets
Assets:
Assets, fair value	32,773	32,998
Basis of Fair Value Measurement, Level 1 | Deferred Compensation Liability | Other Noncurrent Liabilities
Liabilities:
Liabilities, fair value	32,773	32,998
Basis of Fair Value Measurement, Level 2
Assets:
Assets, fair value		12,833
Assets, fair value	1,202
Basis of Fair Value Measurement, Level 2 | Interest Rate Swap Agreements | Accounts Receivable, Net
Assets:
Assets, fair value		3,925
Basis of Fair Value Measurement, Level 2 | Foreign Currency Foreign Exchange Contracts | Other Current Assets
Assets:
Assets, fair value		$ 8,908
Offsetting of assets, fair value	$ 1,202