Derivatives (Effect of Derivative Financial Instruments on Our Consolidated Statements of Operations) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Interest Expense	$ (61,355)	$ (58,430)	$ (70,724)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax	(400)	4,000
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	$ 2,400	2,300
Lycoming Mall [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)		$ 100