Revenue Recognition Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 15,090		$ 15,090		$ 52,924
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with Customer, Performance Obligation Satisfied in Previous Period	$ (4,138)	$ 1,246	$ 35,658	$ 77,473
Contract With Customer Performance Obligation Not Substantially Completed				$ 36,000