Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities
Net income	$ 77,426	$ 67,830
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment	97,148	91,731
Other amortization	4,840	4,792
Provision for loan losses	9,519	2,439
Loans receivable originated and purchased, held for sale	(98,004)	(168,921)
Proceeds from sale of loans receivable, held for sale	98,457	173,267
Deferred income taxes	21,738	(4,463)
Share-based compensation expense	2,011	3,769
Excess tax benefits from share-based payment arrangements	(383)	(984)
Allowance for equity funds used during construction	(3,736)	(3,309)
Change in cash overdraft	0	193
Other	2,982	1,777
Changes in assets and liabilities
Decrease in accounts receivable and unbilled revenues, net	12,894	44,489
Decrease (increase) in fuel oil stock	9,644	(2,362)
Increase in regulatory assets	(11,752)	(19,976)
Increase in accounts, interest and dividends payable	20,837	8,504
Change in prepaid and accrued income taxes and utility revenue taxes	622	(4,390)
Increase in defined benefit pension and other postretirement benefit plans liability	95	218
Change in other assets and liabilities	(18,878)	(26,232)
Net cash provided by operating activities	225,460	168,372
Cash flows from investing activities
Available-for-sale investment securities purchased	(176,598)	(208,110)
Principal repayments on available-for-sale investment securities	102,716	63,568
Proceeds from sale of available-for-sale investment securities	16,423	0
Purchase of stock from Federal Home Loan Bank	(2,773)	0
Redemption of stock from Federal Home Loan Bank	2,233	58,623
Net increase in loans held for investment	(155,930)	(23,206)
Proceeds from sale of commercial loans	14,105	0
Proceeds from sale of real estate acquired in settlement of loans	553	1,258
Capital expenditures	(203,631)	(206,816)
Contributions in aid of construction	16,810	19,089
Other	1,106	3,819
Net cash used in investing activities	(384,986)	(291,775)
Cash flows from financing activities
Net increase in deposit liabilities	206,949	179,856
Net increase in short-term borrowings with original maturities of three months or less	12,922	5,571
Net increase (decrease) in retail repurchase agreements	(27,158)	13,508
Proceeds from other bank borrowings	55,835	10,000
Repayments of other bank borrowings	(84,369)	0
Proceeds from issuance of long-term debt	75,000	0
Repayment of long-term debt	(75,000)	0
Excess tax benefits from share-based payment arrangements	383	984
Net proceeds from issuance of common stock	7,668	104,469
Common stock dividends	(55,591)	(65,140)
Preferred stock dividends of subsidiaries	(946)	(946)
Other	563	246
Net cash provided by financing activities	116,256	248,548
Net increase (decrease) in cash and cash equivalents	(43,270)	125,145
Cash and cash equivalents, beginning of period	300,478	175,542
Cash and cash equivalents, end of period	$ 257,208	$ 300,687