Derivative Financial Instruments (Classification Of Gains And Losses On Interest Rate Derivative Contracts Designated As Hedging Instruments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ (945)	$ (339)
Derivative interest expense	2,793	1,653
Income tax expense (benefit)	23,691	7,704
Net income	37,840	12,305
Amount of loss reclassified from accumulated OCI into income as "Derivative interest expense" (effective portion)	1,848	1,314
Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net income	1,137	808
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative interest expense	1,848	1,314
Income tax expense (benefit)	$ (711)	$ 506