Employee Benefits (Tables)

9 Months Ended

Sep. 30, 2013

Compensation and Retirement Disclosure [Abstract]

Net Periodic Benefit Cost

The components of the net periodic benefit cost for our pension and postretirement benefit plans are as follows:

	Pension Plan						Postretirement Benefit Plan
Three Months Ended September 30,	2013			2012			2013		2012
Net periodic benefit cost
Service cost	$	1,575		$	1,777		$	1,401	$	496
Interest cost	1,295			1,263			472		398
Expected return on plan assets	(1,443		)	(1,341		)	—		—
Amortization of prior service cost	—			2			—		(8		)
Amortization of net loss	1,530			1,035			385		56
Net periodic benefit cost	$	2,957		$	2,736		$	2,258	$	942

	Pension Plan						Postretirement Benefit Plan
Nine Months Ended September 30,	2013			2012			2013		2012
Net periodic benefit cost
Service cost	$	4,725		$	3,846		$	2,906	$	1,488
Interest cost	3,882			3,787			1,319		1,194
Expected return on plan assets	(4,329		)	(4,023		)	—		—
Amortization of prior service cost	—			5			—		(24		)
Amortization of net loss	3,741			3,311			659		168
Net periodic benefit cost	$	8,019		$	6,926		$	4,884	$	2,826