Segment Information (Tables)

12 Months Ended

Dec. 31, 2012

Segment Reporting [Abstract]

Lines of business results and key performance measures

											FirstMerit
December 31, 2012	Commercial		Retail		Wealth			Other			Consolidated
OPERATIONS:
Net interest income	$	258,575	$	207,907	$	17,444		$	(12,096	)	$	471,830
Provision for loan losses	32,319		10,008		(626		)	12,997			54,698
Other income	67,606		103,279		32,996			19,723			223,604
Other expenses	159,525		221,297		39,296			33,495			453,613
Net income	87,318		51,922		7,650			(12,784		)	134,106
AVERAGES:
Assets	6,424,226		2,952,280		238,805			5,005,316			14,620,627
Loans	6,391,189		2,674,997		225,018			65,876			9,357,080
Earnings assets	6,493,713		2,707,632		225,044			3,646,302			13,072,691
Deposits	3,284,722		7,416,982		709,786			142,308			11,553,798
Economic Capital	404,005		212,409		49,313			942,381			1,608,108

										FirstMerit
December 31, 2011	Commercial		Retail		Wealth		Other			Consolidated
OPERATIONS:
Net interest income	$	265,196	$	225,580	$	18,764	$	(29,913	)	$	479,627
Provision for loan losses	38,830		21,672		3,479		10,407			74,388
Other income	57,940		103,248		31,684		31,885			224,757
Other expenses	148,338		235,339		40,004		40,664			464,345
Net income	88,379		46,681		4,527		(20,029		)	119,558
AVERAGES:
Assets	6,203,526		2,935,699		240,952		5,115,153			14,495,330
Loans	6,201,990		2,661,910		227,710		64,363			9,155,973
Earnings assets	6,281,589		2,712,133		228,191		3,506,811			12,728,724
Deposits	3,027,329		7,500,213		644,879		240,080			11,412,501
Economic Capital	368,434		223,772		50,871		905,276			1,548,353

										FirstMerit
December 31, 2010	Commercial		Retail		Wealth		Other			Consolidated
OPERATIONS:
Net interest income	$	250,597	$	214,118	$	19,548	$	(25,744	)	$	458,519
Provision for loan losses	54,065		36,249		2,668		(4,767		)	88,215
Other income	46,876		114,497		32,596		18,587			212,556
Other expenses	110,261		224,334		39,604		68,661			442,860
Net income	86,545		44,220		6,416		(34,272		)	102,909
AVERAGES:
Assets	5,404,883		2,983,395		278,143		4,857,930			13,524,351
Loans	5,394,135		2,698,502		266,522		170,144			8,529,303
Earnings assets	5,456,316		2,742,696		266,835		3,291,138			11,756,985
Deposits	2,516,201		7,015,468		578,876		339,886			10,450,431
Economic Capital	308,547		223,304		36,881		746,889			1,315,621