Fair Value Measurements - Inputs Used to Determine Fair Values of Oreo are Considered Level 3 Inputs in Fair Value Hierarchy (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 823,810		$ 860,082
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	45,499	$ 50,677
Losses From Fair Value Changes	895	753
Impaired loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	32,743	34,672
Losses From Fair Value Changes	245	715
Other Real Estate Owned [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	9,394	11,875
Losses From Fair Value Changes	596	38
Mortgage servicing rights member | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3,362	$ 4,130
Losses From Fair Value Changes	$ 54