Benefit Plans and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2014

Benefit Plans and Other Postretirement Benefits

Schedule of components of net pension expense

	Pension Benefits						Other Postretirement Benefits
	Three months ended June 30,
	2014			2013			2014		2013
Service cost	$	2,049		$	2,103		$	28	$	40
Interest cost	6,035			5,107			123		127
Expected return on plan assets	(7,123		)	(6,071		)	—		—
Amortization of transition obligation	(25		)	(27		)	—		—
Amortization of prior service cost	673			485			—		—
Amortization of net actuarial losses	4,022			5,897			104		193
Net pension expense	$	5,631		$	7,494		$	255	$	360

	Pension Benefits						Other Postretirement Benefits
	Six months ended June 30,
	2014			2013			2014		2013
Service cost	$	4,095		$	4,215		$	55	$	80
Interest cost	12,052			10,314			245		255
Expected return on plan assets	(14,255		)	(12,274		)	—		—
Amortization of transition obligation	(49		)	(54		)	—		—
Amortization of prior service cost	1,346			980			—		—
Amortization of net actuarial losses	8,035			11,802			210		385
Net pension expense	$	11,224		$	14,983		$	510	$	720