ALLOWANCE FOR LOAN LOSSES

The following table presents a summary of changes in the allowance for loan losses by portfolio segment:



Year ended December 31, 2012	Real Estate			Consumer			Commercial			Agriculture			Other		Total
Allowance for loan losses:
Beginning balance	$	87,396		$	8,594		$	15,325		$	1,266		$	—	$	112,581
Provision charged to operating expense	28,651			1,922			10,845			(668		)	—		40,750
Less loans charged-off	(43,506		)	(5,320		)	(11,990		)	(120		)	—		(60,936		)
Add back recoveries of loans previously charged-off	3,241			1,945			2,905			25			—		8,116
Ending balance	$	75,782		$	7,141		$	17,085		$	503		$	—	$	100,511

Individually evaluated for impairment	$	8,350		$	—		$	1,919		$	28		$	—	$	10,297
Collectively evaluated for impairment	67,432			7,141			15,166			475			—		90,214
Ending balance	$	75,782		$	7,141		$	17,085		$	503		$	—	$	100,511

Total loans:
Individually evaluated for impairment	$	123,406		$	—		$	12,242		$	537		$	—	$	136,185
Collectively evaluated for impairment	2,660,420			636,794			676,511			113,090			912		4,087,727
Total loans	$	2,783,826		$	636,794		$	688,753		$	113,627		$	912	$	4,223,912



Year ended December 31, 2011	Real Estate			Consumer			Commercial			Agriculture			Other		Total
Allowance for loan losses:
Beginning balance	$	84,181		$	9,332		$	25,354		$	1,613		$	—	$	120,480
Provision charged to operating expense	46,844			3,566			7,959			(218		)	—		58,151
Less loans charged-off	(45,764		)	(6,043		)	(19,332		)	(142		)	—		(71,281		)
Add back recoveries of loans previously charged-off	2,135			1,739			1,344			13			—		5,231
Ending balance	$	87,396		$	8,594		$	15,325		$	1,266		$	—	$	112,581

Individually evaluated for impairment	$	28,023		$	—		$	4,664		$	151		$	—	$	32,838
Collectively evaluated for impairment	59,373			8,594			10,661			1,115			—		79,743
Ending balance	$	87,396		$	8,594		$	15,325		$	1,266		$	—	$	112,581

Total loans:
Individually evaluated for impairment	$	210,199		$	—		$	19,638		$	759		$	—	$	230,596
Collectively evaluated for impairment	2,544,495			616,071			673,623			118,951			2,813		3,955,953
Total loans	$	2,754,694		$	616,071		$	693,261		$	119,710		$	2,813	$	4,186,549



Year ended December 31, 2010	Real Estate			Consumer			Commercial			Agriculture			Other		Total
Allowance for loan losses:
Beginning balance	$	76,357		$	6,220		$	18,608		$	1,845		$	—	$	103,030
Provision charged to operating expense	42,163			8,636			16,333			(232		)	—		66,900
Less loans charged-off	(34,718		)	(7,577		)	(10,023		)	(21		)	—		(52,339		)
Add back recoveries of loans previously charged-off	379			2,053			436			21			—		2,889
Ending balance	$	84,181		$	9,332		$	25,354		$	1,613		$	—	$	120,480

Individually evaluated for impairment	$	27,081		$	—		$	14,892		$	253		$	—	$	42,226
Collectively evaluated for impairment	57,100			9,332			10,462			1,360			—		78,254
Ending balance	$	84,181		$	9,332		$	25,354		$	1,613		$	—	$	120,480

Total loans:
Individually evaluated for impairment	$	162,804		$	—		$	35,522		$	976		$	—	$	199,302
Collectively evaluated for impairment	2,709,125			646,580			694,949			115,570			2,383		4,168,607
Total loans	$	2,871,929		$	646,580		$	730,471		$	116,546		$	2,383	$	4,367,909

The Company performs a quarterly assessment of the adequacy of its allowance for loan losses in accordance with generally accepted accounting principles. The methodology used to assess the adequacy is consistently applied to the Company's loan portfolio and consists of three elements: (1) specific valuation allowances based on probable losses on impaired loans; (2) historical valuation allowances based on loan loss experience for similar loans with similar characteristics and trends; and (3) general valuation allowances determined based on changes in the nature of the loan portfolio, overall portfolio quality, industry concentrations, delinquency trends, general economic conditions and other qualitative risk factors both internal and external to the Company.

Specific allowances are established for loans where management has determined that probability of a loss exists by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies and any relevant qualitative or environmental factors impacting the loan. Historical valuation allowances are determined by applying percentage loss factors to the credit exposures from outstanding loans. For commercial, agricultural and real estate loans, loss factors are applied based on the internal risk classifications of these loans. For consumer loans, loss factors are applied on a portfolio basis. For commercial, agriculture and real estate loans, loss factor percentages are based on a migration analysis of our historical loss experience, designed to account for credit deterioration. For consumer loans, loss factor percentages are based on a one-year loss history. General valuation allowances are determined by evaluating, on a quarterly basis, changes in the nature and volume of the loan portfolio, overall portfolio quality, industry concentrations, current economic and regulatory factors and the estimated impact of current economic, environmental and regulatory conditions on historical loss rates.