Pension and Other Post-Retirement Benefit Plans - Schedule of Amount Recognized in Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other changes in plan assets and benefit obligations recognized in OCI, net of tax:
Total recognized in OCI, net of tax	$ 901	$ 776	$ (21,501)
Pension Benefits
Other changes in plan assets and benefit obligations recognized in OCI, net of tax:
Net loss (gain)	1,592	558	712
Net prior service (credit) cost	0	0	0
Total recognized in OCI, net of tax	1,592	558	712
Total recognized in net periodic benefit cost and OCI, net of tax	2,929	1,939	959
Other Benefits
Other changes in plan assets and benefit obligations recognized in OCI, net of tax:
Net loss (gain)	(663)	39	2,147
Net prior service (credit) cost	(28)	179	416
Total recognized in OCI, net of tax	(691)	218	2,563
Total recognized in net periodic benefit cost and OCI, net of tax	$ 1,192	$ 2,013	$ 4,137