Securities (Details) - Changes In Credit Losses Recognized In Earnings $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($) security
Changes in Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance		$ 23,709	$ 23,709	$ 23,709	$ 23,880
OTTI included in earnings:
Reduction for sales of securities	[1],[2]	0	0	0	(171)
Ending balance		$ 23,709	$ 23,709	$ 23,709	$ 23,709
Collateralized mortgage obligations (CMOs)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Number of CMOs sold | security					1
Carrying value of CMOs sold					$ 1,300

[1] Included in net securities gains in the Condensed Consolidated Statements of Income.

[2] This reduction was driven by the sale of one CMO with a carrying value of $1.3 million during the six months ended June 30, 201