Commitments: (Tables)

12 Months Ended

Dec. 31, 2015

Commitments:

Schedule of estimated minimum rental commitments for railcar leases for use at coal-fired facilities over the next five years and thereafter

    As of December 31, 2015, our estimated minimum rental commitments for our railcar leases for use at our coal-fired facilities over the next five years and thereafter are as follows:

		(dollars in thousands)
2016	$	5,318
2017		5,318
2018		5,318
2019		2,950
2020		588
Thereafter		–

Schedule of estimated minimum long-term commitments

    As of December 31, 2015, our estimated minimum long-term commitments are as follows:

		(dollars in thousands)
		Coal		Nuclear Fuel
2016	$	29,658	$	55,400
2017		15,342		27,800
2018		8,117		29,200
2019		–		24,300
2020		–		21,700
Thereafter		–		60,800