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Securities - Unrealized Loss Positions (Details) $ in Thousands	Mar. 31, 2019 USD ($) security	Dec. 31, 2018 USD ($) security
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	9	16
Greater than 12 months in an unrealized loss position | security	41	61
Total | security	50	77
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 206	$ 1,256
Greater than 12 months in an unrealized loss position	4,325	7,592
Total	4,531	8,848
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	56,863	86,856
Greater than 12 months in an unrealized loss position	148,615	197,238
Total	$ 205,478	$ 284,094
US Treasury Securities [Member]
Securities Available-for-Sale, Number of Securities
Greater than 12 months in an unrealized loss position | security	1	1
Total | security	1	1
Securities Available-for-Sale, Unrealized Losses
Greater than 12 months in an unrealized loss position	$ 47	$ 83
Total	47	83
Securities Available-for-Sale, Fair Value
Greater than 12 months in an unrealized loss position	3,960	3,923
Total	$ 3,960	$ 3,923
US Government Corporations and Agencies Securities [Member]
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security		3
Greater than 12 months in an unrealized loss position | security	4	1
Total | security	4	4
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position		$ 100
Greater than 12 months in an unrealized loss position	$ 151	61
Total	151	161
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position		7,385
Greater than 12 months in an unrealized loss position	10,360	3,566
Total	$ 10,360	$ 10,951
Mortgage Backed Securities, Issued by US Government Agencies [Member]
Securities Available-for-Sale, Number of Securities
Greater than 12 months in an unrealized loss position | security	10	11
Total | security	10	11
Securities Available-for-Sale, Unrealized Losses
Greater than 12 months in an unrealized loss position	$ 154	$ 377
Total	154	377
Securities Available-for-Sale, Fair Value
Greater than 12 months in an unrealized loss position	9,575	11,439
Total	$ 9,575	$ 11,439
US States and Political Subdivisions Debt Securities [Member]
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	4	4
Greater than 12 months in an unrealized loss position | security	9	33
Total | security	13	37
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 1	$ 126
Greater than 12 months in an unrealized loss position	2,086	4,835
Total	2,087	4,961
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	808	17,713
Greater than 12 months in an unrealized loss position	41,500	110,326
Total	$ 42,308	$ 128,039
Collateralized Mortgage Obligations [Member]
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security		2
Greater than 12 months in an unrealized loss position | security	11	10
Total | security	11	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position		$ 309
Greater than 12 months in an unrealized loss position	$ 1,206	1,835
Total	1,206	2,144
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position		15,211
Greater than 12 months in an unrealized loss position	53,431	43,687
Total	$ 53,431	$ 58,898
Asset-backed Securities [Member]
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	1
Greater than 12 months in an unrealized loss position | security	2	4
Total | security	3	4
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 46
Greater than 12 months in an unrealized loss position	104	$ 225
Total	150	225
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	27,731
Greater than 12 months in an unrealized loss position	4,952	16,473
Total	$ 32,683	$ 16,473
Collateralized loan obligations
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	4	7
Greater than 12 months in an unrealized loss position | security	4	1
Total | security	8	8
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 159	$ 721
Greater than 12 months in an unrealized loss position	577	176
Total	736	897
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	28,324	46,547
Greater than 12 months in an unrealized loss position	24,837	7,824
Total	$ 53,161	$ 54,371

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