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Securities, Available for Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt securities, available-for-sale [Abstract]
Amortized cost	$ 1,318,711	$ 968,554
Unrealized gains	32,166	8,319
Unrealized losses	2,179	1,533
Estimated fair value	1,348,698	975,340
Allowance for credit losses on AFS securities	0
Components of net realized gains (losses) on sale of AFS securities [Abstract]
Gross realized gains	3	73	$ 0
Gross realized (losses)	0	(152)	(6,622)
Net AFS realized gains (losses)	3	(79)	(6,622)
Gains from calls on securities available for sale	3	25	$ 0
Federal Agency [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	245,590	34,998
Unrealized gains	59	3
Unrealized losses	2,052	243
Estimated fair value	243,597	34,758
State & Municipal [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	42,550	2,533
Unrealized gains	630	0
Unrealized losses	0	20
Estimated fair value	43,180	2,513
Mortgage-Backed, Government Sponsored Enterprises [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	521,448	453,614
Unrealized gains	17,079	4,982
Unrealized losses	22	239
Estimated fair value	538,505	458,357
Mortgage-backed Securities, U.S. Government Agency Securities [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	55,049	44,758
Unrealized gains	2,332	667
Unrealized losses	47	156
Estimated fair value	57,334	45,269
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	311,710	328,499
Unrealized gains	7,549	1,949
Unrealized losses	58	467
Estimated fair value	319,201	329,981
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	114,864	104,152
Unrealized gains	3,739	718
Unrealized losses	0	408
Estimated fair value	118,603	$ 104,462
Corporate [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	27,500
Unrealized gains	778
Unrealized losses	0
Estimated fair value	$ 28,278

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