Benefit Plans - Schedule of Information Related to Investment in Level 3 Assets (Details) - Level 3 - Pension Benefits - Astoria Bank	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Minimum
Significant unobservable inputs:
Composite market value factor	0.979	0.996
Gross guaranteed crediting rate	0.0250	0.0285
Maximum
Significant unobservable inputs:
Composite market value factor	1.037	1.137
Gross guaranteed crediting rate	0.0365	0.0335