Fair Value Measurements (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Gains (losses) related to assets or liabilities measured on a recurring basis using significant unobservable inputs	$ 0	$ 0
Impaired loans not covered under loss-share agreements	9,608,000	4,406,000
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific reserve included in allowance for loan losses	46,211,000	42,737,000
MSR impairment (recovery)	0	40,000	$ 0
Net loss resulting from fair value changes of these mortgage loans	1,594,000
Impaired Loans, Not Covered
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific reserve included in allowance for loan losses	$ 357,000	$ 305,000