Fair Value Measurements Fair Value Measurements (Schedule Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) - Equity Method Investments [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3, beginning of period, Financial Assets	$ 5,502
Unrealized gain included in net income	613
Purchases/capital funding	1,399
Payments	(54)
Level 3, end of period, Financial Assets	$ 7,460