Proceeds From Sales and Calls of Investment Securities and Associates Gains or Losses (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Available-for-sale
Proceeds from sales and calls of investment securities		$ 155,894	$ 59,974	$ 268,557	$ 148,458
Gross realized gains	[1]	278	366	3,345	1,309
Gross realized losses	[1]	(201)	(960)	(3,864)	(1,960)
Held-to-maturity
Proceeds from calls of investment securities		3,675	340	18,910	21,965
Gross realized gains	[1]	0	0	153	91
Gross realized losses	[1]	$ 0	$ 0	$ (179)	$ (146)

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