Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Contractual Maturities and Estimated Fair Values) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Amortized Cost
Due in one year or less, held-to-maturity debt securities amortized cost	$ 1,200,000		$ 1,200,000
Due after one year through five years, held-to-maturity debt securities amortized cost	2,200,000		2,200,000
Amortized cost, held-to-maturity debt securities	3,400,000		3,400,000		$ 3,400,000
Fair Value
Due in one year or less, held-to-maturity debt securities, Estimated fair value	1,200,000		1,200,000
Due after one year through five years, held-to-maturity debt securities, Estimated fair value	2,200,000		2,200,000
Estimated fair value	3,400,000		3,400,000		3,400,000
Available-for-sale debt securities amortized cost disclosures
Due in one year or less, available-for-sale debt securities amortized cost	49,533,000		49,533,000
Due after ten years, available-for-sale debt securities amortized cost	110,430,000		110,430,000
Residential mortgage-backed securities, amortized cost	4,636,564,000		4,636,564,000
Amortized cost, Available-for-sale securities	4,796,527,000		4,796,527,000		4,254,960,000
Available for sale debt securities, Estimated Fair Value Disclosures
Due in one year or less, available-for-sale debt securities, Estimated Fair Value	48,992,000		48,992,000
Due after ten years, available-for-sale debt securities, Estimated Fair Value	103,109,000		103,109,000
Residential mortgage-backed securities, Estimated Fair Value	4,063,289,000		4,063,289,000
Estimated fair value, Available for sale securities	4,215,390,000		4,215,390,000		$ 4,213,920,000
Available for sale debt securities, Estimated Fair Value Disclosures
Proceeds from sales and calls of available for sale securities	800,000	$ 3,025,000	800,000	$ 5,890,000
Proceeds from sales of mortgage-backed securities	0	0	0	0
Gross gains realized on sales	0	0	0	0
Gross losses realized on sales	0	$ 12,000	0	$ 16,000
Collateral Pledged
Available-for-sale debt securities amortized cost disclosures
Amortized cost, Available-for-sale securities	1,595,549,000		1,595,549,000
Available for sale debt securities, Estimated Fair Value Disclosures
Fair value of available for sale investment securities pledged	$ 1,360,046,000		$ 1,360,046,000