Employee Benefit Plans - Actual and Target Allocations of Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Document Fiscal Year Focus	2015
U.S. Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 552,817	$ 601,376	$ 595,143
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual plan asset allocations	100.00%	100.00%
Target plan asset allocations	100.00%
U.S. Pension Plan, Defined Benefit [Member] | Collective trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 118,299	$ 119,312
U.S. Pension Plan, Defined Benefit [Member] | Equity securities [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual plan asset allocations	57.00%	55.00%
Target plan asset allocations	58.00%
U.S. Pension Plan, Defined Benefit [Member] | Fixed income investments [Member]
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual plan asset allocations	33.00%	36.00%
Target plan asset allocations	35.00%
U.S. Pension Plan, Defined Benefit [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 42,391	$ 37,145
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Actual plan asset allocations	10.00%	9.00%
Target plan asset allocations	7.00%
Level 3 [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 8,904	$ 9,976	$ 14,937
Level 1 [Member] | U.S. Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	257,210	275,178
Level 1 [Member] | U.S. Pension Plan, Defined Benefit [Member] | Collective trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Level 1 [Member] | U.S. Pension Plan, Defined Benefit [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Level 2 [Member] | U.S. Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	295,607	326,198
Level 2 [Member] | U.S. Pension Plan, Defined Benefit [Member] | Collective trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	118,299	119,312
Level 2 [Member] | U.S. Pension Plan, Defined Benefit [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 42,391	$ 37,145