Securities - Estimated Fair Value and Unrealized Loss for Securities Available-for-Sale and Held-to-Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Available-for-sale, less than 12 months, estimated fair value	$ 56,632	$ 21,795
Available-for-sale, less than 12 months, unrealized losses	(57)	(6)
Available-for-sale, 12 months or longer, estimated fair value	0	0
Available-for-sale, 12 months or longer, unrealized losses	0	0
Available-for-sale, total, estimated fair value	56,632	21,795
Available-for-sale, total, unrealized losses	(57)	(6)
Held-to-maturity, less than 12 months, estimated fair value	430,630	86,523
Held-to-maturity, less than 12 months, unrealized losses	(5,184)	(546)
Held-to-maturity, 12 months or longer, estimated fair value	8,445	46,965
Held-to-maturity, 12 months or longer, unrealized losses	(271)	(2,680)
Held-to-maturity, total, estimated fair value	439,075	133,488
Held-to-maturity, total, unrealized losses	(5,455)	(3,226)
Total securities, less than 12 months, estimated fair value	487,262	108,318
Total securities, less than 12 months, unrealized losses	(5,241)	(552)
Total securities, 12 months or longer, estimated fair value	8,445	46,965
Total securities, 12 months or longer, unrealized losses	(271)	(2,680)
Total securities, estimated fair value	495,707	155,283
Total securities, unrealized losses	(5,512)	(3,232)
U.S. government and agency obligations | Securities Investment
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Available-for-sale, less than 12 months, estimated fair value	15,114	17,029
Available-for-sale, less than 12 months, unrealized losses	(9)	(2)
Available-for-sale, 12 months or longer, estimated fair value	0	0
Available-for-sale, 12 months or longer, unrealized losses	0	0
Available-for-sale, total, estimated fair value	15,114	17,029
Available-for-sale, total, unrealized losses	(9)	(2)
Corporate debt securities | Securities Investment
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Available-for-sale, less than 12 months, estimated fair value	997
Available-for-sale, less than 12 months, unrealized losses	(3)
Available-for-sale, 12 months or longer, estimated fair value	0
Available-for-sale, 12 months or longer, unrealized losses	0
Available-for-sale, total, estimated fair value	997
Available-for-sale, total, unrealized losses	(3)
Held-to-maturity, less than 12 months, estimated fair value	37,888	10,192
Held-to-maturity, less than 12 months, unrealized losses	(1,471)	(255)
Held-to-maturity, 12 months or longer, estimated fair value	507	35,935
Held-to-maturity, 12 months or longer, unrealized losses	(3)	(2,397)
Held-to-maturity, total, estimated fair value	38,395	46,127
Held-to-maturity, total, unrealized losses	(1,474)	(2,652)
CLOs
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Available-for-sale, less than 12 months, estimated fair value		4,766
Available-for-sale, less than 12 months, unrealized losses		(4)
Available-for-sale, 12 months or longer, estimated fair value		0
Available-for-sale, 12 months or longer, unrealized losses		0
Available-for-sale, total, estimated fair value		4,766
Available-for-sale, total, unrealized losses		(4)
CLOs | Securities Investment
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Available-for-sale, less than 12 months, estimated fair value	40,521
Available-for-sale, less than 12 months, unrealized losses	(45)
Available-for-sale, 12 months or longer, estimated fair value	0
Available-for-sale, 12 months or longer, unrealized losses	0
Available-for-sale, total, estimated fair value	40,521
Available-for-sale, total, unrealized losses	(45)
State, municipal and sovereign debt obligations | Securities Investment
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	58,149	2,823
Held-to-maturity, less than 12 months, unrealized losses	(427)	(23)
Held-to-maturity, 12 months or longer, estimated fair value	5,877	7,509
Held-to-maturity, 12 months or longer, unrealized losses	(263)	(208)
Held-to-maturity, total, estimated fair value	64,026	10,332
Held-to-maturity, total, unrealized losses	(690)	(231)
Mortgage-backed securities:
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	334,593	73,508
Held-to-maturity, less than 12 months, unrealized losses	(3,286)	(268)
Held-to-maturity, 12 months or longer, estimated fair value	2,061	3,521
Held-to-maturity, 12 months or longer, unrealized losses	(5)	(75)
Held-to-maturity, total, estimated fair value	336,654	77,029
Held-to-maturity, total, unrealized losses	(3,291)	(343)
Mortgage-backed securities: | FHLMC
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	160,445	24,661
Held-to-maturity, less than 12 months, unrealized losses	(1,846)	(117)
Held-to-maturity, 12 months or longer, estimated fair value	0	669
Held-to-maturity, 12 months or longer, unrealized losses	0	(7)
Held-to-maturity, total, estimated fair value	160,445	25,330
Held-to-maturity, total, unrealized losses	(1,846)	(124)
Mortgage-backed securities: | FNMA
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	166,605	39,365
Held-to-maturity, less than 12 months, unrealized losses	(1,376)	(128)
Held-to-maturity, 12 months or longer, estimated fair value	272	939
Held-to-maturity, 12 months or longer, unrealized losses	(3)	(19)
Held-to-maturity, total, estimated fair value	166,877	40,304
Held-to-maturity, total, unrealized losses	(1,379)	(147)
Mortgage-backed securities: | GNMA
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	5,924	5,856
Held-to-maturity, less than 12 months, unrealized losses	(22)	(11)
Held-to-maturity, 12 months or longer, estimated fair value	0	207
Held-to-maturity, 12 months or longer, unrealized losses	0	(1)
Held-to-maturity, total, estimated fair value	5,924	6,063
Held-to-maturity, total, unrealized losses	(22)	(12)
Mortgage-backed securities: | SBA
Schedule Of Available For Sale Securities And Held To Maturity Securities [Line Items]
Held-to-maturity, less than 12 months, estimated fair value	1,619	3,626
Held-to-maturity, less than 12 months, unrealized losses	(42)	(12)
Held-to-maturity, 12 months or longer, estimated fair value	1,789	1,706
Held-to-maturity, 12 months or longer, unrealized losses	(2)	(48)
Held-to-maturity, total, estimated fair value	3,408	5,332
Held-to-maturity, total, unrealized losses	$ (44)	$ (60)