Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2015

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
	2015			2014			2015		2014
Service cost	$	3,990		$	3,231		$	—	$	25
Interest cost	5,003			4,695			203		(63		)
Expected return on assets	(5,323		)	(4,768		)	—		—
Amortization:
Prior service cost	81			529			—		—
Actuarial (gain) loss	3,533			2,035			30		3
Actuarial valuation adjustment	—			—			—		460
Direct recognition of expense	—			131			166		114
Net periodic benefit cost	$	7,284		$	5,853		$	399	$	539
	Nine Months Ended September 30,
	Pension Benefits						Other Benefits
	2015			2014			2015		2014
Service cost	$	11,971		$	9,694		$	—	$	74
Interest cost	15,009			14,333			610		234
Expected return on assets	(15,969		)	(14,273		)	—		—
Amortization:
Prior service cost	244			1,586			—		—
Actuarial (gain)/loss	10,601			6,127			90		3
Actuarial valuation adjustment	—			—			—		460
Direct recognition of expense	—			131			493		10
Net periodic benefit cost	$	21,856		$	17,598		$	1,193	$	781

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, 2015 and the prior-year end.

Pension Assets by Component

	September 30, 2015			December 31, 2014
	Amount		%	Amount		%
Corporate debt	$	153,536	49	$	166,825	52
Other fixed maturities	279		—	284		—
Equity securities	121,199		39	127,568		39
Short-term investments	16,414		5	9,038		3
Guaranteed annuity contract	16,973		6	15,027		5
Other	3,571		1	4,156		1
Total	$	311,972	100	$	322,898	100