Qualified Employee Benefit Plans - Net (Benefit) Expense Under the Retirement Plan (Details) - Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligations	$ 4,816	$ 4,895	$ 4,640
Expected return on plan assets	(6,176)	(6,493)	(5,347)
Amortization of transition asset	0	0	(47)
Recognized actuarial loss	979	490	1,109
Net pension (benefit) expense	$ (381)	$ (1,108)	$ 355