Securities (Details 2) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014 item	Dec. 31, 2013 item
Securities
Available for sale, fair value	$ 852,836,000	$ 841,310,000
Held to maturity, fair value	1,859,000	831,000
General obligation bonds
Securities
Number of issuers	210	219
Average Exposure Per Issuer (Fair Value)	982,000	1,020,000
Amortized Cost	204,119,000	222,693,000
Fair Value	206,143,000	223,470,000
Amount of largest exposure to a single issuer	3,400,000	5,000,000
Percentage of the entity's stockholders equity in excess of aggregate book or market value	10.00%	10.00%
Percentage of underlying asset rated by at least a specified nationally recognized statistical rating organization	96.90%	96.40%
Minimum number of nationally recognized statistical rating organizations	1	1
Percentage of underlying asset unrated	3.10%	3.60%
General obligation bonds | Illinois
Securities
Number of issuers	75	82
Average Exposure Per Issuer (Fair Value)	935,000	1,022,000
Amortized Cost	68,919,000	82,884,000
Fair Value	70,109,000	83,804,000
General obligation bonds | Wisconsin
Securities
Number of issuers	41	41
Average Exposure Per Issuer (Fair Value)	981,000	1,052,000
Amortized Cost	39,996,000	43,117,000
Fair Value	40,203,000	43,122,000
General obligation bonds | Michigan
Securities
Number of issuers	37	37
Average Exposure Per Issuer (Fair Value)	960,000	956,000
Amortized Cost	35,289,000	35,350,000
Fair Value	35,520,000	35,365,000
General obligation bonds | Pennsylvania
Securities
Number of issuers	11	11
Average Exposure Per Issuer (Fair Value)	1,287,000	1,285,000
Amortized Cost	14,112,000	14,132,000
Fair Value	14,153,000	14,133,000
General obligation bonds | Ohio
Securities
Number of issuers	11	12
Average Exposure Per Issuer (Fair Value)	1,012,000	952,000
Amortized Cost	11,220,000	11,709,000
Fair Value	11,129,000	11,426,000
General obligation bonds | Texas
Securities
Number of issuers	7	7
Average Exposure Per Issuer (Fair Value)	1,051,000	1,039,000
Amortized Cost	7,474,000	7,510,000
Fair Value	7,355,000	7,270,000
General obligation bonds | Iowa
Securities
Number of issuers	3	3
Average Exposure Per Issuer (Fair Value)	2,049,000	2,020,000
Amortized Cost	6,123,000	6,126,000
Fair Value	6,146,000	6,060,000
General obligation bonds | Other
Securities
Number of issuers	25	26
Average Exposure Per Issuer (Fair Value)	861,000	857,000
Amortized Cost	20,986,000	21,865,000
Fair Value	21,528,000	22,290,000
Revenue bonds
Securities
Number of issuers	45	48
Average Exposure Per Issuer (Fair Value)	1,076,000	1,032,000
Amortized Cost	48,731,000	50,218,000
Fair Value	48,415,000	49,513,000
Amount of largest exposure to a single issuer	3,000,000	3,000,000
Percentage of the entity's stockholders equity in excess of aggregate book or market value	10.00%
Minimum number of nationally recognized statistical rating organizations	1	1
Revenue bonds | Illinois
Securities
Number of issuers	4	4
Average Exposure Per Issuer (Fair Value)	1,803,000	1,780,000
Amortized Cost	7,354,000	7,356,000
Fair Value	7,213,000	7,121,000
Revenue bonds | Indiana
Securities
Number of issuers	11	14
Average Exposure Per Issuer (Fair Value)	1,202,000	1,034,000
Amortized Cost	13,321,000	14,740,000
Fair Value	13,219,000	14,481,000
Revenue bonds | Other
Securities
Number of issuers	30	30
Average Exposure Per Issuer (Fair Value)	933,000	930,000
Amortized Cost	28,056,000	28,122,000
Fair Value	27,983,000	27,911,000
Obligations of states and political subdivisions
Securities
Available for sale, fair value	253,722,000	272,152,000
Held to maturity, fair value	836,000	831,000
Number of issuers	255	267
Total Risk Based Capital for rated securities (as a percent)	100.00%
Total Risk Based Capital for unrated securities (as a percent)	15.00%
Obligations of states and political subdivisions | General obligation bonds
Securities
Fair Value	206,100,000	223,500,000
Number of states in which investment is held	24	25
Number of states in which investment is held in excess of aggregate fair value	7	7
Aggregate fair value	5,000,000	5,000,000
Obligations of states and political subdivisions | Revenue bonds
Securities
Fair Value	48,400,000	49,500,000
Number of states in which investment is held	21	21
Number of states in which investment is held in excess of aggregate fair value	2	2
Aggregate fair value	$ 5,000,000	$ 5,000,000