Investments is Low Income Housing Tax Credits Investments in Qualified Affordable Housing Projects (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018		Dec. 31, 2017
Investments in Affordable Housing Projects [Abstract]
Original investment value	$ 47,408		$ 47,399
Amortization Method Qualified Affordable Housing Project Investments	34,153		35,225
Capital commitment relating to low income housing project investments	3,332		4,536
Tax credits and benefits	5,494	[1]	5,654
Amortization of investments	4,330	[2]	4,402	[3]
Net income tax benefit	$ 1,165	[4]	$ 1,253

[1] (1) This amount reflects anticipated tax credits and tax benefits for the full year ended December 31, 2018.

[2] (2) The amortization amount reduces the tax credits and benefits anticipated for the full year ended December 31, 2018.

[3] (4) The 2017 amount is inclusive of $466,000 related to the revaluation of Low Income Housing tax credit investments as a result of the Tax Act.

[4] (3) This amount represents the net tax benefit expected to be realized for the full year ended December 31, 2018 in determining the Company's effective tax rate.