CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash Flows From Operating Activities:
Net income	$ 12,105	$ 11,870
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,275	3,112
Net gains on sales of securities	(3,137)	(2,134)
Provision for loan losses	500	800
Stock-based compensation expense	918	702
Increase in income tax liability	1,109	890
Increase in pension liability	1,253	203
Other operating activities, net	(1,459)	1,263
Net cash provided by operating activities	14,564	16,706
Cash Flows From Investing Activities:
Proceeds from sales of securities available-for-sale	63,660	29,749
Proceeds from maturities of securities available-for-sale	6,803	5,940
Purchase of securities available-for-sale	(16,030)	(49,042)
Net decrease (increase) in loans	16,406	(22,978)
Increase in payments in excess of funding	(10,451)	(7,763)
Purchases of premises and equipment, net	(2,284)	(768)
Environmental management acquisition		(7,798)
Net cash provided by (used in) investing activities	58,104	(52,660)
Cash Flows From Financing Activities:
Net (decrease) increase in noninterest-bearing demand deposits	(8,237)	605
Net decrease in interest-bearing demand and savings deposits	(9,519)	(27,722)
Net decrease in time deposits	(4,943)	(10,188)
Net increase (decrease) in accounts and drafts payable	83,309	(2,382)
Cash dividends paid	(4,135)	(3,531)
Distribution of stock awards, net	(378)	(128)
Net cash provided by (used in) financing activities	56,097	(43,346)
Net increase (decrease) in cash and cash equivalents	128,765	(79,300)
Cash and cash equivalents at beginning of period	141,088	235,962
Cash and cash equivalents at end of period	269,853	156,662
Supplemental information:
Cash paid for interest	1,398	1,624
Cash paid for income taxes	$ 2,991	$ 3,373