Proceeds From Sales and Calls of Debt Securities and Associates Gains or Losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Available-for-sale
Sales of available-for-sale debt securities		$ 37,711	$ 172,323	$ 114,784	$ 476,371
Gross realized gains	[1]	142	1,347	1,104	4,284
Gross realized losses	[1]	(14)	(1,213)	(114)	(3,929)
Held-to-maturity
Proceeds from calls of debt securities		0	2,630	20,250	32,575
Gross realized gains	[1]	0	0	1	2
Gross realized losses	[1]	$ 0	$ 0	$ 0	$ (10)

[1] The gain or loss on the sale or call of each debt security is determined by the specific identification method.