Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Consolidated Statements of Comprehensive Income
Net unrealized gains (losses) on securities arising during the period, taxes	$ 5,485	$ (721)	$ 6,032	$ (572)
Less: reclassification adjustment for net realized gains included in net income, taxes	488	53	488	53
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	3,630	2,405	7,476	4,878
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	$ 3,184	$ 2,095	$ 6,568	$ 4,257