Employee Benefit Plans: Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Pension Plan [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Net loss	$ 0	$ 0
Prior service cost	0	0
Total accumulated other comprehensive income (loss)	0	0
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net loss	1,297
Prior service cost	28
Total net periodic benefit cost expected to be recognized during calendar year 2016	1,325
Supplemental Non-qualified Defined Benefit Retirement Plans [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Net loss	673	(801)
Prior service cost	0	0
Total accumulated other comprehensive income (loss)	673	(801)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net loss	53
Prior service cost	0
Total net periodic benefit cost expected to be recognized during calendar year 2016	53
Non-pension Defined Benefit Postretirement Healthcare Plan [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Net loss	0	0
Prior service cost	0	0
Total accumulated other comprehensive income (loss)	0	$ 0
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net loss	0
Prior service cost	(218)
Total net periodic benefit cost expected to be recognized during calendar year 2016	$ (218)