Commitments and Contingencies (Changes in Environmental Liability) (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 21,365	$ 21,651	$ 13,241	$ 13,942
Additions to accrual	0	0	10,000	0
Expenditures for remediation	286	286	1,590	701
Ending balance	$ 21,079	$ 21,365	$ 21,651	$ 13,241