5. Employee Benefit Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Employee Benefit Plan Details
Service cost	$ 157,968	$ 162,083
Interest cost	113,224	102,736
Expected return on plan assets	$ (213,604)	$ (209,704)
Amortization of net obligation at transition
Amortization of prior service cost	$ (3,809)	$ (3,809)
Amortization of net loss	55,786	45,160
Net periodic pension cost	$ 109,565	$ 96,466