Fair Value Measurements - (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Fair Value Measurements (Textual) [Abstract]
Impaired loans not covered under loss-share agreements	$ 4,562,000		$ 7,191,000
Changes in fair value, gain (loss)	5,527,000	$ 27,000
Impairment losses on mortgage servicing rights	0	$ 0
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific reserve included in allowance for loan losses	42,859,000		42,437,000
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	$ 1,102,000		$ 683,000