XML 80 R59.htm IDEA: XBRL DOCUMENT v3.7.0.1
Fair Value Measurements - Level 3 Rollforward Derivatives (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Net derivative balance at beginning of period $ (41,685) $ (39,507) $ (47,406) $ (32,979)
Included in OCI (6) 104 (6) 104
Deferred as a regulatory asset or liability 4,252 1,499 (7,503) (7,604)
Settlements 1,699 4,502 3,122 6,267
Transfers into Level 3 from Level 2 (4,350) 120 (4,388) 382
Transfers from Level 3 into Level 2 3,845 902 19,936 1,450
Net derivative balance at end of period (36,245) (32,380) (36,245) (32,380)
Net unrealized gains included in earnings related to instruments still held at end of period $ 0 $ 0 $ 0 $ 0