Fair Value Measurements (Schedule Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3, beginning of period, Financial Assets	$ 8,802
Level 3, beginning of period, Contingent Liability	6,000
Gain included in net income	3,039
Purchases/capital funding	1,682
Receipts	(8,021)
Payments	(6,000)
Level 3, end of period, Financial Assets	5,502
Level 3, end of period, Contingent Liability	0
Equity Method Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3, beginning of period, Financial Assets	3,471
Gain included in net income	349
Purchases/capital funding	1,682
Level 3, end of period, Financial Assets	5,502
Contingent Asset [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3, beginning of period, Financial Assets	5,331
Gain included in net income	2,690
Receipts	(8,021)
Level 3, end of period, Financial Assets	$ 0