Recently Issued Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Federal corporate tax rate	21.00%	35.00%
Reduction in tax rate	14.00%
Revenues within scope of updated accounting guidance	$ 40,540	$ 43,859
ASU 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of standard tax effects on AOCI and retained earnings			$ 0
ASU 2018-02 [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of standard tax effects on AOCI and retained earnings			(2,100)
ASU 2018-02 [Member] | Accumulated Other Comprehensive Income [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of standard tax effects on AOCI and retained earnings			2,100
ASU 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment that increased retained earnings and decreased AOCI			0
ASU 2016-01 [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment that increased retained earnings and decreased AOCI			9,825
ASU 2016-01 [Member] | Accumulated Other Comprehensive Income [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment that increased retained earnings and decreased AOCI			$ (9,825)
ASU 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues within scope of updated accounting guidance	$ 28
Revenues within scope of updated accounting guidance, as a percentage of total revenues (less than)	0.10%