Summary of Assets and Liabilities Recorded at Fair Value on Recurring Basis (Detail) - Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets:
Assets, fair value	$ 188,977	$ 213,370
Liabilities:
Liabilities, fair value	33,871	32,998
Money Market Mutual Funds | Other Assets
Assets:
Assets, fair value	111,652	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	43,046	55,594
Deferred Compensation Assets | Other Assets
Assets:
Assets, fair value	33,871	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	(1,794)
Deferred Compensation Liability | Other Noncurrent Liabilities
Liabilities:
Liabilities, fair value	33,871	32,998
Basis of Fair Value Measurement, Level 1
Assets:
Assets, fair value	190,771	200,537
Liabilities:
Liabilities, fair value	33,871	32,998
Basis of Fair Value Measurement, Level 1 | Money Market Mutual Funds | Other Assets
Assets:
Assets, fair value	111,652	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	43,046	55,594
Basis of Fair Value Measurement, Level 1 | Deferred Compensation Assets | Other Assets
Assets:
Assets, fair value	33,871	32,998
Basis of Fair Value Measurement, Level 1 | Deferred Compensation Liability | Other Noncurrent Liabilities
Liabilities:
Liabilities, fair value	33,871	32,998
Basis of Fair Value Measurement, Level 2
Assets:
Assets, fair value		12,833
Assets, fair value	(1,794)
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	$ (1,794)