Other Real Estate - Changes and Gains, Net on Other Real Estate (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Reconciliation Of Carrying Amount Of Real Estate Investments Roll Forward
Balance at beginning of period	[1]	$ 62,051	$ 78,828		$ 98,569
Additions	[2]	9,235	24,525	[1]	32,782	[1]
Disposals		(24,762)	(36,801)	[1]	(48,352)	[1]
Write-downs		(3,296)	(4,501)	[1]	(4,171)	[1]
Balance at end of period		43,228	62,051	[1]	78,828	[1]
Gain, net on the sale of other real estate included in other real estate expense		$ 2,087	$ 7,031	[1]	$ 4,041	[1]

[1] The changes and gains, net on other real estate for the years ended December 31, 2016 and 2015 include covered other real estate.

[2] For the year ended December 31, 2017, additions to other real estate included $475 thousand of other real estate acquired in the Reliance merger on April 7, 2017