STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income	$ 7,371	$ 4,653	$ 79,828	$ 73,183
Other comprehensive income (loss), net of tax
Change in pension and postretirement benefit plan liability, net of tax of $(88), $49, $(264) and $98, respectively	141	(78)	423	(156)
Other comprehensive income (loss), net of tax	141	(78)	423	(156)
Comprehensive income	$ 7,512	$ 4,575	$ 80,251	$ 73,027