Basis of Presentation and Significant Accounting Policies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Aug. 14, 2017
Schedule of Equity Method Investments [Line Items]
Number of segments | segment	2
Residential Mortgage Holding Company
Schedule of Equity Method Investments [Line Items]
Ownership percentage	100.00%
NBG
Schedule of Equity Method Investments [Line Items]
Ownership percentage			50.10%
Accounting Standards Update 2016-01
Schedule of Equity Method Investments [Line Items]
Cumulative effect of new accounting principle		$ 0
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive Income (Loss)
Schedule of Equity Method Investments [Line Items]
Cumulative effect of new accounting principle		(191)
Accounting Standards Update 2016-01 | Retained Earnings
Schedule of Equity Method Investments [Line Items]
Cumulative effect of new accounting principle		191
Accounting Standards Update 2017-08
Schedule of Equity Method Investments [Line Items]
Cumulative effect of new accounting principle		(62)
Accounting Standards Update 2017-08 | Retained Earnings
Schedule of Equity Method Investments [Line Items]
Cumulative effect of new accounting principle	$ (62)	$ (62)