Debt Securities Held to Maturity Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) security	Jun. 30, 2019 USD ($) security	Jun. 30, 2020 USD ($) security	Jun. 30, 2019 USD ($) security	Dec. 31, 2019 USD ($) security
Schedule of Held-to-maturity Securities [Line Items]
Debt securities, held-to-maturity	$ 273,997,000		$ 273,997,000		$ 285,756,000
Fair value	289,836,000		289,836,000		289,505,000
Proceeds from sale of held-to-maturity securities	0	$ 0	0	$ 0
Proceeds from sale and maturity of held-to-maturity securities	20,000,000	5,000,000	20,000,000.0	5,000,000.0
Debt securities, held-to-maturity, sold, realized gain (loss)	0	$ 0	0	$ 0
Debt securities, held-to-maturity, number of debt securities called | security		1		1
Fair value of securities sold under agreements to repurchase	$ 240,000,000.0		$ 240,000,000.0		$ 236,000,000.0
Number of positions | security	5		5		22
Other-than-temporary impairment loss, held-to-maturity, before tax	$ 0	$ 0	$ 0	$ 0
Mortgage-backed securities and collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Debt securities, held-to-maturity	273,997,000		273,997,000		$ 265,756,000
Fair value	$ 289,836,000		$ 289,836,000		$ 269,545,000