Proceeds From Sales and Calls of Investment Securities and Associates Gains or Losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Available-for-sale
Proceeds from sales and calls of investment securities		$ 104,172	$ 29,861	$ 112,663	$ 88,484
Gross realized gains	[1]	3,057	143	3,067	943
Gross realized losses	[1]	(3,514)	(261)	(3,663)	(1,000)
Held-to-maturity
Proceeds from calls of investment securities		7,445	10,470	15,235	21,625
Gross realized gains	[1]	72	44	153	91
Gross realized losses	[1]	$ (137)	$ (146)	$ (179)	$ (146)

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