1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Retirement and Other Employee Benefits (Details) - USD ($)		12 Months Ended
	Mar. 01, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined benefit pension plan
Retirement and Other Employee Benefits
Obligation for defined benefit plans		$ 0
Pension costs under defined benefit plan		4,977,000	$ 5,591,000	$ 8,321,000
Postretirement benefits
Retirement and Other Employee Benefits
Pension costs under defined benefit plan		232,000	197,000	321,000
Postretirement benefits
Retirement and Other Employee Benefits
Amount expensed under defined contribution plan		$ 6,096,000	$ 6,006,000	$ 5,781,000
Subsequent Event
Retirement and Other Employee Benefits
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 0