Securities - Securities In An Unrealized Loss Position (Details) $ in Thousands	Jun. 30, 2021 USD ($) security	Dec. 31, 2020 USD ($) security
Securities available-for-sale
Number of Securities | security	289	178
Available-for-Sale, Fair Value
Less Than 12 Months	$ 1,221,832	$ 682,644
12 Months or Longer	112,716	123,370
Total	1,334,548	806,014
Unrealized Losses
Less Than 12 Months	30,139	8,628
12 Months or Longer	3,445	1,585
Total	$ 33,584	$ 10,213
U.S. agency securities
Securities available-for-sale
Number of Securities | security	64	48
Available-for-Sale, Fair Value
Less Than 12 Months	$ 376,464	$ 253,841
12 Months or Longer	51,780	14,932
Total	428,244	268,773
Unrealized Losses
Less Than 12 Months	13,721	4,764
12 Months or Longer	1,651	212
Total	$ 15,372	$ 4,976
CMOs
Securities available-for-sale
Number of Securities | security	150	104
Available-for-Sale, Fair Value
Less Than 12 Months	$ 568,946	$ 349,853
12 Months or Longer	26,307	86,618
Total	595,253	436,471
Unrealized Losses
Less Than 12 Months	12,450	3,205
12 Months or Longer	1,151	1,118
Total	$ 13,601	$ 4,323
MBSs
Securities available-for-sale
Number of Securities | security	62	19
Available-for-Sale, Fair Value
Less Than 12 Months	$ 265,493	$ 69,838
12 Months or Longer	31,417	12,307
Total	296,910	82,145
Unrealized Losses
Less Than 12 Months	3,739	550
12 Months or Longer	629	90
Total	$ 4,368	$ 640
Municipal securities
Securities available-for-sale
Number of Securities | security	12	4
Available-for-Sale, Fair Value
Less Than 12 Months	$ 10,929	$ 1,012
12 Months or Longer	0	0
Total	10,929	1,012
Unrealized Losses
Less Than 12 Months	229	4
12 Months or Longer	0	0
Total	$ 229	$ 4
Corporate debt securities
Securities available-for-sale
Number of Securities | security	1	3
Available-for-Sale, Fair Value
Less Than 12 Months	$ 0	$ 8,100
12 Months or Longer	3,212	9,513
Total	3,212	17,613
Unrealized Losses
Less Than 12 Months	0	105
12 Months or Longer	14	165
Total	$ 14	$ 270