Commitments and Contingencies, Variable Interest Entities (Details) - Low-Income Housing Limited Partnerships - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amounts Reflected in Consolidated Balance Sheets [Abstract]
Current assets	$ 377	$ 246
Property, plant and equipment, net	2,199	2,278
Other noncurrent assets	127	122
Total assets	2,703	2,646
Current liabilities	1,246	1,349
Mortgages and other long-term debt payable	537	486
Other noncurrent liabilities	51	48
Total liabilities	$ 1,834	$ 1,883