Investment Securities (Schedule of Investment Securities Available for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	$ 9,666,799	$ 10,328,650
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2,722	2,854
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	602,081	677,061
Debt Securities, Available-for-sale	9,067,440
Debt Securities, Available-for-Sale and Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	9,676,799	10,338,650
Debt Securities, Available-for-sale and Held-to-maturity	9,077,440	9,664,443
Investment securities (including securities reported at fair value of $9,133,937 and $9,745,327)	9,143,937	9,755,327
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	119,454	148,956
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	63
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	12,004	13,178
Debt Securities, Available-for-sale	107,450	135,841
U.S. Government agency and sponsored enterprise residential MBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	2,000,621	2,036,693
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,220	1,334
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	48,385	54,859
Debt Securities, Available-for-sale	1,953,456	1,983,168
U.S. Government agency and sponsored enterprise commercial MBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	577,961	600,517
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	152	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	69,832	75,423
Debt Securities, Available-for-sale	508,281	525,094
Private label residential MBS and CMOs
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	2,702,029	2,864,589
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	161	54
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	318,209	333,980
Debt Securities, Available-for-sale	2,383,981	2,530,663
Private label commercial MBS
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	2,380,013	2,645,168
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	364	176
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	98,661	120,990
Debt Securities, Available-for-sale	2,281,716	2,524,354
Single family real estate-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	462,100	502,194
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	23,537	31,753
Debt Securities, Available-for-sale	438,563	470,441
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	1,099,890	1,166,838
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	381	151
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	19,244	30,526
Debt Securities, Available-for-sale	1,081,027	1,136,463
Non-mortgage asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	95,512	102,194
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,679	6,218
Debt Securities, Available-for-sale	91,833	95,976
State and municipal obligations
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	108,383	122,181
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	201	695
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,971	6,215
Debt Securities, Available-for-sale	103,613	116,661
SBA securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss	120,836	139,320
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	243	381
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,559	3,919
Debt Securities, Available-for-sale	117,520	135,782
Investment securities held to maturity
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale		9,654,443
Investment securities held to maturity	10,000	10,000
Marketable equity securities
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI	$ 66,497	$ 90,884