Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 62,137	$ 57,665
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	183	(1,229)
Total other comprehensive loss	183	(1,229)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	62,320	56,436
Net income attributable to noncontrolling interests	(21)	(16)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 62,299	$ 56,420