Employee Benefit Plans (Defined Benefit Plans Disclosure) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,586	$ 2,489	$ 4,616	$ 3,990
Interest cost	1,283	1,487	2,526	2,295
Expected return on plan assets	(1,331)	(1,302)	(2,449)	(2,235)
Amortization of prior service cost	80	216	163	218
Amortization of prior actuarial loss	833	245	1,272	918
Total	3,451	3,135	6,128	5,186
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	589	470	1,178	940
Interest cost	491	339	982	677
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Amortization of prior actuarial loss	265	217	530	434
Total	$ 1,345	$ 1,026	$ 2,690	$ 2,051