Discontinued Operations (Assets and Liabilities of Discontinued Operations) (Detail) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets of Discontinued Operations:
Receivables, net of allowance for bad debt	$ 0	$ 6
Prepaid expenses	0	8
Assets	0	14	$ 104,967
Liabilities of Discontinued Operations:
Accounts payable	0	67
Other accrued expenses	0	5,228
Liabiltiies	$ 0	$ 5,295