Goodwill (Changes in Goodwill) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance, beginning of year, Goodwill, gross	$ 323,713	$ 323,510
Balance, beginning of year, Accumulated impairment lossses	(310,653)	(310,653)
Balance, beginning of year, Goodwill, Net	13,060	12,857
Increases (decreases) due to current year acquisitions (disposals)	4,367	0
Effects of foreign currency translation	(472)	203
Total goodwill increase (decrease)	3,895	203
Balance, end of year, Goodwill, gross	327,608	323,713
Balance, end of year, Accumulated impairment lossses	(310,653)	(310,653)
Balance, end of year, Goodwill, Net	$ 16,955	$ 13,060