Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 7,533	$ 8,792	$ 16,996
Charged to Income	1,693	1,178	1,227
Acquisition of business	3	0	0
Deductions	1,939	2,437	9,431
Balance at End of Year	7,290	7,533	8,792
Tax valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	15,103	33,303	32,370
Charged to Income	291	680	3,635
Acquisition of business	7,484	0	0
Deductions	2,650	18,880	2,702
Balance at End of Year	$ 20,228	$ 15,103	$ 33,303