Federal Home Loan Bank Advances (Summary of Outstanding FHLB Advances) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Federal Home Loan Bank advances	$ 1,228,429	$ 674,870
1.75% advance due June 2020
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	1.75%
Federal Home Loan Bank advances	$ 0	3,981
1.72% advance due June 2020
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	1.72%
Federal Home Loan Bank advances	$ 0	2,487
1.88% advance due June 2021
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	1.88%
Federal Home Loan Bank advances	$ 2,987	2,960
0.00% advance due May 2021
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	0.00%
Federal Home Loan Bank advances	$ 60,000	0
0.00% advance due April 2024
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	0.00%
Federal Home Loan Bank advances	$ 442	442
2.98% advance due August 2024
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	2.98%
Federal Home Loan Bank advances	$ 25,000	25,000
2.05% variable-rate advance due January 2028
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	2.05%
Federal Home Loan Bank advances	$ 100,000	100,000
2.18% advance due February 2029
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	2.18%
Federal Home Loan Bank advances	$ 440,000	440,000
1.36% advance due December 2029
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	1.36%
Federal Home Loan Bank advances	$ 100,000	100,000
1.11% advance due February 2030
Federal Home Loan Bank, Advances, Branch Of FHLB Bank [Line Items]
Interest rate	1.11%
Federal Home Loan Bank advances	$ 500,000	$ 0