Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2013

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefits Cost

The following table shows the components of net periodic benefits cost included in expense for the plans.

	Three Months ended September 30,
	2013			2012			2013		2012
							Other Post-
	Pension benefits						retirement Benefits
Service cost	$	3,969		$	3,249		$	52	$	48
Interest cost		4,151			4,301			327		361
Expected return on plan assets		(6,982	)		(6,350	)		—		—
Amortization of prior service cost		—			—			—		(13	)
Amortization of net loss		1,605			1,645			459		176
Amortization of transition obligation		—			—			—		1
Net periodic benefit cost	$	2,743		$	2,845		$	838	$	573

	Nine Months Ended September 30,
	2013			2012			2013		2012
	Pension benefits						Other Post- retirement Benefits
Service cost	$	11,905		$	9,743		$	162	$	144
Interest cost		12,457			12,904			987		1,083
Expected return on plan assets		(20,946	)		(19,049	)		—		—
Amortization of prior service cost		—			—			—		(41	)
Amortization of net loss		4,813			4,936			1,320		530
Amortization of transition obligation		—			—			—		4
Net periodic benefit cost	$	8,229		$	8,534		$	2,469	$	1,720