Fair Value Measurements - (Details Textual) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value Measurements (Textual) [Abstract]
Impaired loans not covered under loss-share agreements	$ 4,063,000		$ 4,406,000
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific reserve included in allowance for loan losses	44,149,000		42,737,000
Impairment losses on mortgage servicing rights	0	$ 40,000	40,000
Changes in fair value, gain (loss)	6,092,000	$ 6,172,000
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	$ 674,000		$ 305,000