Sale of Branches (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Jan. 17, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans, net of deferred fees and costs		$ 23,604,633	$ 22,177,069
Deposits		$ 24,648,060	$ 23,242,661
Trust One Bank, Memphis, Tennessee [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans, net of deferred fees and costs				$ 89,600
Deposits				$ 191,300
Gain on disposition of business	$ 5,800