STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 93,660	$ 90,835
Other comprehensive income (loss), net of tax
Change in pension and postemployment benefit plan liability, net of tax of $(53) and (351), respectively	160	(80)
Other comprehensive income, net of tax	160	(80)
Comprehensive income	$ 93,820	$ 90,755