Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pre-Tax Amount
Other Comprehensive Income/(Loss), Pre-Tax Amount	$ 3,234	$ 4,523	$ (6,821)	$ 26,552
Tax (Expense) Benefit
Other Comprehensive Income/(Loss), Tax (Expense) Benefit	(690)	(963)	1,455	(5,650)
Net of Tax Amount
Other Comprehensive Income/(Loss), Net of Tax Amount	2,544	3,560	(5,366)	20,902
Pension settlement charge	200		900
Accumulated Net Investment Gain (Loss) Attributable to Parent
Pre-Tax Amount
Change in net unrealized gains/(losses) on debt securities available-for-sale	324	4,059	(9,388)	25,623
Tax (Expense) Benefit
Change in net unrealized gains/(losses) on debt securities available-for-sale	(69)	(864)	2,003	(5,452)
Net of Tax Amount
Change in net unrealized gains/(losses) on debt securities available-for-sale	255	3,195	(7,385)	20,171
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Pre-Tax Amount
Other Comprehensive Income/(Loss), Pre-Tax Amount	2,910	464	2,567	929
Tax (Expense) Benefit
Other Comprehensive Income/(Loss), Tax (Expense) Benefit	(621)	(99)	(548)	(198)
Net of Tax Amount
Other Comprehensive Income/(Loss), Net of Tax Amount	$ 2,289	$ 365	$ 2,019	$ 731