Employee Benefit Plan - Summary of Components of Net Periodic Pension Cost (Benefit) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Service cost	$ 225	$ 889	$ 3,059
Interest cost	653	712	1,225
Expected return on assets	(443)	(2,315)	(3,038)
Amortization of prior service costs	0	440	649
Amortization of loss	326	48	0
Settlement charges	739	1,162	3,698
One-time charge in connection with an increase in benefits for certain participants	0	0	1,401
Curtailment charge	0	2,063	2,173
Net periodic pension cost	1,500	2,999	9,167
Other changes in plan assets and obligations recognized in Other comprehensive income:
Prior service cost	0	(2,503)	(769)
(Gain) loss	(3,260)	1,275	(2,531)
Total other comprehensive income	(3,260)	(1,228)	(3,300)
Total net periodic pension cost and other comprehensive income (loss)	$ (1,760)	$ 1,771	$ 5,867