CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income	$ 202,120	$ 196,960	$ 162,703
Other comprehensive income (loss), net of tax:
Reclassification of net income (loss) on derivative instruments	452	498	371
Postretirement medical liability adjustment	(131)	213	773
Foreign currency translation adjustment	(35)	270	(202)
Total Other Comprehensive Income (Loss)	286	981	942
Comprehensive Income	$ 202,406	$ 197,941	$ 163,645

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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