Securities (Unrealized Loss NOT deemed to be OTTI) (Details) $ in Thousands	Jun. 30, 2019 USD ($) holding	Dec. 31, 2018 USD ($) holding
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	35	205
Fair value, less than 12 months	$ 37,732	$ 202,901
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(101)	(2,486)
Fair value, 12 months or longer	108,166	566,107
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(1,830)	(16,926)
Fair value, Total	145,898	769,008
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (1,931)	$ (19,412)
U.S. Government agency securities
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	3
Fair value, less than 12 months	$ 9,998	$ 9,960
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(6)	(43)
Fair value, 12 months or longer	0	22,078
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months		(396)
Fair value, Total	9,998	32,038
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (6)	$ (439)
Agency mortgage-backed securities
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	11	144
Fair value, less than 12 months	$ 0	$ 104,616
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months		(1,363)
Fair value, 12 months or longer	16,365	222,850
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(87)	(5,147)
Fair value, Total	16,365	327,466
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (87)	$ (6,510)
Agency Collateralized Mortgage Obligations [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	19	48
Fair value, less than 12 months	$ 25,527	$ 57,871
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(85)	(398)
Fair value, 12 months or longer	82,547	279,229
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(1,341)	(9,957)
Fair value, Total	108,074	337,100
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (1,426)	$ (10,355)
Single issuer trust preferred securities issued by banks and insurers
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	2	2
Fair value, less than 12 months	$ 2,207	$ 2,197
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(10)	(20)
Fair value, 12 months or longer	0	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	0	0
Fair value, Total	2,207	2,197
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (10)	$ (20)
Pooled trust preferred securities issued by banks and insurers
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	1
Fair value, less than 12 months	$ 0	$ 0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	0	0
Fair value, 12 months or longer	1,281	1,329
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(372)	(349)
Fair value, Total	1,281	1,329
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (372)	$ (349)
Small Business Administration Pooled Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	7
Fair value, less than 12 months	$ 0	$ 28,257
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	0	(662)
Fair value, 12 months or longer	7,973	40,621
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(30)	(1,077)
Fair value, Total	7,973	68,878
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (30)	$ (1,739)