Income Taxes, Textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Valuation allowance for deferred tax assets	$ 269,000	$ 0	$ 0
Deferred Other Tax Expense (Benefit)	12,000,000
Other Tax Expense (Benefit)	1,000,000
Bad debt from acquired savings banks	100,000,000
Deferred tax on bad debt from acquired savings banks	25,000,000
Unrecognized tax benefit impact on effective tax rate	3,000,000	7,000,000
Interest and penalty expense (benefit)	(1,000,000)	0
Accrued interest and penalties	1,000,000	$ 2,000,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	78,000,000
Operating tax loss carryforwards from acquisitions	16,000,000
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	3,000,000
Operating tax loss carryforwards from acquisitions	$ 3,000,000