Employee Benefit Plans (Defined Benefit Plans Disclosure) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,306	$ 2,030
Interest cost	1,259	1,243
Expected return on plan assets	(1,224)	(1,118)
Amortization of prior service cost	78	83
Amortization of prior actuarial loss	857	439
Total	3,276	2,677
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,016	589
Interest cost	643	491
Expected return on plan assets	0	0
Amortization of prior service cost	0	0
Amortization of prior actuarial loss	616	265
Total	$ 2,275	$ 1,345