Goodwill (Changes in Goodwill) (Detail) - USD ($)		12 Months Ended
	Jan. 18, 2019	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance, beginning of year, Goodwill, gross		$ 327,608,000	$ 323,713,000
Balance, beginning of year, Accumulated impairment lossses		(310,653,000)	(310,653,000)
Balance, beginning of year, Goodwill, Net		16,955,000	13,060,000
Increases (decreases) due to current year acquisitions (disposals)	$ 45,500,000	45,520,000	4,367,000
Effects of foreign currency translation		(47,000)	(472,000)
Total goodwill increase (decrease)		45,473,000	3,895,000
Balance, end of year, Goodwill, gross		373,081,000	327,608,000
Balance, end of year, Accumulated impairment lossses		(310,653,000)	(310,653,000)
Balance, end of year, Goodwill, Net		$ 62,428,000	$ 16,955,000