Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 21,722	$ 27,287	$ 83,859	$ 84,952
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	183	140	366	(1,089)
Total other comprehensive loss	183	140	366	(1,089)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	21,905	27,427	84,225	83,863
Net income attributable to noncontrolling interests	49	(33)	28	(49)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 21,954	$ 27,394	$ 84,253	$ 83,814