Retirement Plans, Fair Value of Pension Plan Investments Table (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Plan Investments
Money market account	$ 3,624	$ 481
Common /collective trust funds (1)	126,741	120,136
Mutual funds	165,353	168,982
Total Retirement Account Plan Investments	295,718	289,599
Fair Value, Inputs, Level 1
Pension Plan Investments
Money market account	3,624	481
Common /collective trust funds (1)	126,741	120,136
Mutual funds	165,353	168,982
Total Retirement Account Plan Investments	295,718	289,599
Fair Value, Inputs, Level 2
Pension Plan Investments
Money market account	0	0
Common /collective trust funds (1)	0	0
Mutual funds	0	0
Total Retirement Account Plan Investments	0	0
Fair Value, Inputs, Level 3
Pension Plan Investments
Money market account	0	0
Common /collective trust funds (1)	0	0
Mutual funds	0	0
Total Retirement Account Plan Investments	$ 0	$ 0