Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Summary of Post-Retirement Benefit Costs by Component

The following tables present a summary of post-retirement benefit costs by component.

Components of Post-Retirement Benefit Costs

	Three Months Ended September 30,
	Pension Benefits						Other Benefits
	2016			2015			2016		2015
Service cost	$	3,894		$	3,990		$	—	$	—
Interest cost	5,430			5,003			212		203
Expected return on assets	(5,782		)	(5,323		)	—		—
Amortization:
Prior service cost	120			81			—		—
Actuarial (gain) loss	2,423			3,533			8		30
Direct recognition of expense	—			—			45		166
Net periodic benefit cost	$	6,085		$	7,284		$	265	$	399
	Nine Months Ended September 30,
	Pension Benefits						Other Benefits
	2016			2015			2016		2015
Service cost	$	11,682		$	11,971		$	—	$	—
Interest cost	16,294			15,009			636		610
Expected return on assets	(17,346		)	(15,969		)	—		—
Amortization:
Prior service cost	360			244			—		—
Actuarial (gain)/loss	7,270			10,601			24		90
Direct recognition of expense	—			—			99		493
Net periodic benefit cost	$	18,260		$	21,856		$	759	$	1,193

Schedule of Assets at Fair Value for Defined-Benefit Pension Plans

The following table presents assets at fair value for the defined-benefit pension plans at September 30, 2016 and the prior-year end.

Pension Assets by Component

	September 30, 2016			December 31, 2015
	Amount		%	Amount		%
Corporate debt	$	171,896	52	$	146,381	47
Other fixed maturities	276		—	270		—
Equity securities	127,708		39	123,428		40
Short-term investments	4,811		1	15,593		5
Guaranteed annuity contract	17,426		5	17,082		6
Other	8,287		3	4,842		2
Total	$	330,404	100	$	307,596	100