XML 67 R53.htm IDEA: XBRL DOCUMENT v3.6.0.2
Retirement Plans, Summary of Change in Plan Assets (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Pension Benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets at beginning of year $ 243,588 $ 242,275
Actual return on plan assets 20,723 (2,426)
Employer contribution 0 10,000
Gross benefits paid (6,794) (6,261)
Fair value of plan assets at end of year 257,517 243,588
SERP [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets at beginning of year 0 0
Actual return on plan assets 0 0
Employer contribution 146 145
Gross benefits paid (146) (145)
Fair value of plan assets at end of year 0 0
Other Postretirement Benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets at beginning of year 0 0
Actual return on plan assets 0 0
Employer contribution 47 88
Gross benefits paid (47) (88)
Fair value of plan assets at end of year $ 0 $ 0