Pension Plan and Employee Benefits, 401 (K) Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
401(k) Plan [Abstract]
401 (k) Plan expense	$ 5,029	$ 4,730	$ 4,422
Other Subsidiaries [Member]
401(k) Plan [Abstract]
401 (k) Plan expense	$ 900	$ 900	$ 1,000