Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Federal corporate tax rate	21.00%	35.00%
Reclassification upon ASU implementation		$ 1,500
ASU 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		0
AOCI [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		(2,600)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		1,500
Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		400
AOCI [Member] | ASU 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		(5,575)
Retained Earnings [Member] | ASU 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification upon ASU implementation		$ 5,575