Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Schedule of Post-Retirement Benefit Costs

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

Components of Post-Retirement Benefit Costs

	Three Months ended March 31,
	Pension Benefits						Other Benefits
	2015			2014			2015		2014
Service cost	$	3,990		$	3,232		$	—	$	56
Interest cost	5,003			4,819			203		147
Expected return on assets	(5,323		)	(4,753		)	—		—
Amortization:
Prior service cost	81			528			—		—
Actuarial (gain) loss	3,534			2,044			23		—
Direct recognition of expense	—			—			176		(62		)
Net periodic benefit cost	$	7,285		$	5,870		$	402	$	141

Schedule of Defined-Benefit Plans Disclosures

The following chart presents assets at fair value for the defined-benefit pension plans at March 31, 2015 and the prior-year end.

Pension Assets by Component

	March 31, 2015			December 31, 2014
	Amount		%	Amount		%
Corporate debt	$	169,188	52	$	166,825	52
Other fixed maturities	292		—	284		—
Equity securities	128,137		40	127,568		39
Short-term investments	7,798		2	9,038		3
Guaranteed annuity contract	15,144		5	15,027		5
Other	3,684		1	4,156		1
Total	$	324,243	100	$	322,898	100