CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive income:
Net income	$ 94,629	$ 6,924	[1]
Pension and retiree medical benefits:
Amortization of losses (gains) included in net periodic benefit cost, net of tax of $15 and ($4), respectively	19	(6)
Derivative instruments:
Net fair value decrease, net of tax of $(1) and $(4), respectively	(1)	(6)
Reclassification of losses to net income, net of tax of $154 and $143, respectively	223	208
Total derivative instruments, net of tax	222	202
Marketable securities:
Net fair value increase, net of tax of $0 and $0, respectively	0	1
Other comprehensive income	241	197
Comprehensive income	$ 94,870	$ 7,121

[1] Includes a net of tax charge related to the Monticello LCM/EPU project. See Note 5.