Regulatory Capital and Reserve Requirements (Tables)

12 Months Ended

Dec. 31, 2012

Banking and Thrift [Abstract]

Corporation's and Chemical Bank's actual capital amounts and ratios with the quantitative measures established by regulation to ensure capital adequacy

The summary below compares the Corporation's and Chemical Bank's actual capital amounts and ratios with the quantitative measures established by regulation to ensure capital adequacy:

	Actual				Minimum Required for Capital Adequacy Purposes				Required to be Well Capitalized Under Prompt Corrective Action Regulations
	Capital Amount		Ratio		Capital Amount		Ratio		Capital Amount		Ratio
	(Dollars in thousands)
December 31, 2012
Total Capital to Risk-Weighted Assets:
Corporation	$	552,171	13.2	%	$	334,140	8.0	%	N/A		N/A
Chemical Bank	536,223		12.9		333,195		8.0		$	416,494	10.0	%
Tier 1 Capital to Risk-Weighted Assets:
Corporation	499,563		12.0		167,070		4.0		N/A		N/A
Chemical Bank	483,761		11.6		166,598		4.0		249,896		6.0
Leverage Ratio:
Corporation	499,563		9.2		217,145		4.0		N/A		N/A
Chemical Bank	483,761		8.9		216,784		4.0		270,980		5.0
December 31, 2011
Total Capital to Risk-Weighted Assets:
Corporation	$	517,547	13.3	%	$	310,316	8.0	%	N/A		N/A
Chemical Bank	510,290		13.2		310,119		8.0		$	387,649	10.0	%
Tier 1 Capital to Risk-Weighted Assets:
Corporation	468,565		12.1		155,158		4.0		N/A		N/A
Chemical Bank	461,338		11.9		155,060		4.0		232,589		6.0
Leverage Ratio:
Corporation	468,565		9.0		208,013		4.0		N/A		N/A
Chemical Bank	461,338		8.9		208,033		4.0		260,042		5.0