Unrealized Losses (Details 4) $ in Thousands	Dec. 31, 2019 USD ($) holding	Dec. 31, 2018 USD ($) holding
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	32	205
Fair value, less than 12 months	$ 89,834	$ 202,901
Fair value, 12 months or longer	40,229	566,107
Fair value, Total	130,063	769,008
Unrealized losses, Total	(1,368)	(19,412)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(329)	(2,486)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(1,039)	$ (16,926)
U.S. government agency securities
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	10,000
Summary of gross unrealized losses and fair value of investments
No of holdings | holding		3
Fair value, less than 12 months		$ 9,960
Fair value, 12 months or longer		22,078
Fair value, Total		32,038
Unrealized losses, Total		(439)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months		(43)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months		$ (396)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	10,003
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	10,002
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	12,471
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	12,958
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	0
Agency mortgage-backed securities [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 0
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	12	144
Fair value, less than 12 months	$ 34,009	$ 104,616
Fair value, 12 months or longer	243	222,850
Fair value, Total	34,252	327,466
Unrealized losses, Total	(61)	(6,510)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(59)	(1,363)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(2)	$ (5,147)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	70,945
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	54,798
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	56,181
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	117,805
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	119,514
Single issuer trust preferred securities issued by banks [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	0
Summary of gross unrealized losses and fair value of investments
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	0
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	488
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	493
Agency collateralized mortgage obligations [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 0
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	17	48
Fair value, less than 12 months	$ 48,476	$ 57,871
Fair value, 12 months or longer	37,382	279,229
Fair value, Total	85,858	337,100
Unrealized losses, Total	(868)	(10,355)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(215)	(398)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(653)	$ (9,957)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	0
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	87,305
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	88,511
US States and Political Subdivisions Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	0
Summary of gross unrealized losses and fair value of investments
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	1,188
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	189
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	203
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	$ 0
Single issuer trust preferred securities issued by banks and insurers
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	2
Fair value, less than 12 months	$ 0	$ 2,197
Fair value, 12 months or longer	1,490	0
Fair value, Total	1,490	2,197
Unrealized losses, Total	(10)	(20)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	0	(20)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(10)	$ 0
Pooled trust preferred securities issued by banks and insurers
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 0
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	1
Fair value, less than 12 months	$ 0	$ 0
Fair value, 12 months or longer	1,114	1,329
Fair value, Total	1,114	1,329
Unrealized losses, Total	(374)	(349)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	0	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(374)	$ (349)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	0
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	1,488
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	1,114
Small Business Administration Pooled Securities [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 0
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	7
Fair value, less than 12 months	$ 7,349	$ 28,257
Fair value, 12 months or longer	0	40,621
Fair value, Total	7,349	68,878
Unrealized losses, Total	(55)	(1,739)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(55)	(662)
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	0	$ (1,077)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	0
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	54,024
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	$ 54,795