CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current Assets:
Cash and cash equivalents	$ 9,822	$ 5,928
Restricted cash	6,700	12,716
Accounts receivable, net	143,695	147,151
Inventories	54,161	59,532
Regulatory assets	40,301	48,900
Deferred income taxes	37,143	6,522
Other	11,306	9,450
Total current assets	303,128	290,199
Property, plant, and equipment, net	2,435,590	2,213,267
Goodwill	355,128	355,128
Regulatory assets	367,890	308,804
Other noncurrent assets	23,797	43,040
Total assets	3,485,533	3,210,438
Current Liabilities:
Current maturities of capital leases	1,612	1,370
Current maturities of long-term debt	0	3,792
Short-term borrowings	122,934	166,934
Accounts payable	83,746	76,735
Accrued expenses	192,548	193,939
Regulatory liabilities	48,425	33,184
Total current liabilities	449,265	475,954
Long-term capital leases	31,562	32,918
Long-term debt	1,055,074	905,049
Deferred income taxes	363,928	282,406
Noncurrent regulatory liabilities	276,618	265,987
Other noncurrent liabilities	375,054	389,012
Total liabilities	2,551,501	2,351,326
Commitments and Contingencies (Note 19)
Shareholders' Equity:
Common stock, par value $0.01; authorized 200,000,000 shares; issued and outstanding 40,792,449 and 37,221,344 respectively; Preferred stock, par value $0.01; authorized 50,000,000 shares; none issued	408	398
Treasury stock at cost	(90,702)	(90,273)
Paid-in capital	849,218	816,700
Retained earnings	172,791	128,631
Accumulated other comprehensive income	2,317	3,656
Total shareholders' equity	934,032	859,112
Total liabilities and shareholders' equity	$ 3,485,533	$ 3,210,438