Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities arising during the period, taxes	$ (1,679)	$ 5,485	$ (3,343)	$ 6,032
Less: reclassification adjustment for net realized gains included in net income, taxes	0	488	1,132	488
Less: reclassification adjustment to net income, tax benefits	(38)	(38)	(75)	(75)
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, tax benefits	(1,742)	(3,630)	(3,538)	(7,476)
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	$ 1,641	$ 3,184	$ 3,239	$ 6,568