Schedule of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Income Tax Disclosure [Line Items] | |||
Beginning balance, as of January 1 | $ 38,958 | $ 36,792 | $ 30,418 |
Tax positions for current year, Additions | 8,208 | 9,766 | 6,626 |
Tax positions for prior years, Additions | 199 | 187 | 792 |
Tax positions for prior years, Reductions | (10,573) | (1,960) | (708) |
Expiration of statutes, Reductions | (325) | (3,532) | |
Settlements with tax authorities, Reductions | (204) | (2,295) | (336) |
Ending balance as of December 31 | $ 36,263 | $ 38,958 | $ 36,792 |