Income Taxes Components of Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Deferred Tax Assets, Advances and Contributions	$ 15,598	$ 15,214
Deferred tax assets:
Unamortized investment tax credit	741	773
Pensions and postretirement benefits	4,405	4,565
California franchise tax	1,107	1,193
Net operating loss	5,814	6,439
Other	1,596	1,505
Total deferred tax assets	29,261	29,689
Deferred tax liabilities:
Utility plant	125,706	110,983
Pension and postretirement benefits	25,649	46,315
Investment in stock	3,228	2,487
Deferred gain and other-property related	13,107	14,440
Debt reacquisition costs	496	545
Other	1,811	2,498
Total deferred tax liabilities	169,997	177,268
Net deferred tax liabilities	140,736	147,579
Federal
Deferred tax liabilities:
Net operating loss carryforward	16,610
Operating loss carryforward as reported on tax return	$ 18,234