Sale of Branches (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	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	$ 22,177,069	$ 20,836,382
Deposits	23,242,661	$ 21,531,700
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