Securities Available-for-Sale - Fair Value and Age of Gross Unrealized Losses by Investment Category (Details) $ in Thousands	Mar. 31, 2017 USD ($) security	Dec. 31, 2016 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	32	31
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 269,522	$ 267,500
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (3,250)	$ (3,472)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	32	31
Available-for-sale Securities, Fair Value, Total	$ 269,522	$ 267,500
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (3,250)	$ (3,472)
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	1	1
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 9,849	$ 9,811
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (91)	$ (127)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	1	1
Available-for-sale Securities, Fair Value, Total	$ 9,849	$ 9,811
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (91)	$ (127)
Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	7	7
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 62,308	$ 62,483
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (421)	$ (383)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	7	7
Available-for-sale Securities, Fair Value, Total	$ 62,308	$ 62,483
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (421)	$ (383)
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	9	10
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 74,604	$ 83,031
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (773)	$ (734)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	9	10
Available-for-sale Securities, Fair Value, Total	$ 74,604	$ 83,031
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (773)	$ (734)
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	2	2
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 9,692	$ 10,022
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (236)	$ (232)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	2	2
Available-for-sale Securities, Fair Value, Total	$ 9,692	$ 10,022
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (236)	$ (232)
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	12	10
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 113,000	$ 96,576
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (1,727)	$ (1,950)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	12	10
Available-for-sale Securities, Fair Value, Total	$ 113,000	$ 96,576
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,727)	$ (1,950)
Obligations of States and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	0	1
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 5,577
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ (46)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	0	1
Available-for-sale Securities, Fair Value, Total	$ 0	$ 5,577
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ (46)
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	31	31
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 269,453	$ 267,500
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (3,248)	$ (3,472)
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	31	31
Available-for-sale Securities, Fair Value, Total	$ 269,453	$ 267,500
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (3,248)	$ (3,472)
Marketable Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions \| security	1	0
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 69	$ 0
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (2)	$ 0
Available-for-sale, Securities, 12 Months or More, Number of Positions \| security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions \| security	1	0
Available-for-sale Securities, Fair Value, Total	$ 69	$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (2)	$ 0

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

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-Publisher FASB
-Name Accounting Standards Codification
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