CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Utility Plant
Plant in Service	$ 5,975,139	$ 5,618,435
Utility Plant Under Capital Leases	167,413	131,705
Construction Work in Progress	129,955	102,028
Total Utility Plant	6,272,507	5,852,168
Accumulated Depreciation and Amortization	(2,385,053)	(2,194,301)
Accumulated Amortization of Capital Lease Assets	(104,648)	(99,638)
Total Utility Plant, Net	3,782,806	3,558,229
Investments and Other Property	45,020	39,569
Current Assets
Cash and Cash Equivalents	35,962	55,684
Accounts Receivable, Net	124,934	136,682
Fuel Inventory	25,887	34,600
Materials and Supplies	97,126	94,003
Regulatory Assets	56,340	51,841
Derivative Instruments	4,966	1,808
Assets Held for Sale, Net	0	21,550
Other	13,793	25,904
Total Current Assets	359,008	422,072
Regulatory and Other Assets
Regulatory Assets	225,453	212,312
Derivative Instruments	330	430
Other	37,372	16,866
Total Regulatory and Other Assets	263,155	229,608
Total Assets	4,449,989	4,249,478
Capitalization
Common Stock (No Par Value, 75,000,000 Shares Authorized, 32,139,434 Shares Outstanding as of December 31, 2016 and 2015)	1,296,539	1,296,539
Capital Stock Expense	(6,357)	(6,357)
Retained Earnings	273,408	189,317
Accumulated Other Comprehensive Loss	(4,555)	(4,564)
Total Common Stock Equity	1,559,035	1,474,935
Preferred Stock (No Par Value, 1,000,000 Shares Authorized, None Outstanding as of December 31, 2016 and 2015)	0	0
Capital Lease Obligations	39,267	55,324
Long-Term Debt, Net	1,453,072	1,451,720
Total Capitalization	3,051,374	2,981,979
Current Liabilities
Current Obligations Under Capital Leases	51,765	14,114
Accounts Payable	89,797	86,274
Accrued Taxes Other than Income Taxes	37,639	37,577
Accrued Employee Expenses	29,465	27,718
Accrued Interest	14,508	14,246
Regulatory Liabilities	76,069	53,077
Customer Deposits	25,778	20,349
Derivative Instruments	2,641	12,174
Other	17,837	7,533
Total Current Liabilities	345,499	273,062
Regulatory and Other Liabilities
Deferred Income Taxes, Net	529,148	468,024
Regulatory Liabilities	300,700	307,286
Pension and Other Postretirement Benefits	131,630	120,336
Derivative Instruments	2,629	4,067
Other	89,009	94,724
Total Regulatory and Other Liabilities	1,053,116	994,437
Commitments and Contingencies
Total Capitalization and Other Liabilities	$ 4,449,989	$ 4,249,478