Revenue Recognition and Accounts Receivable - Schedule of Net Increase to Opening Retained Earnings Due to Cumulative Impact of Adopting (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 77,056		$ 81,157
Accounts receivable, net of allowances of $8,934 and $8,405, respectively	77,182		63,437
Inventories	77,686		81,330
Prepaid expenses and other current assets	31,219		25,877
Total current assets	263,143		251,801
Deferred income taxes	28,359		23,315
Other long-term assets	6,814		21,073
Total assets	409,004		405,354
Total liabilities	95,830		108,746
Shareholders’ equity
Common shares	1,841		1,828
Additional paid-in capital	228,356		220,591
Retained earnings	78,493		70,402
Accumulated other comprehensive income	4,484		3,787
Total shareholders’ equity	313,174		296,608
Total liabilities and shareholders’ equity	$ 409,004		405,354
Effect before Topic 606 [Member]
Current assets
Cash and cash equivalents			81,157
Accounts receivable, net of allowances of $8,934 and $8,405, respectively			63,437
Inventories			81,330
Prepaid expenses and other current assets			25,877
Total current assets			251,801
Deferred income taxes			23,315
Other long-term assets			130,238
Total assets			405,354
Total liabilities			108,746
Shareholders’ equity
Common shares			1,828
Additional paid-in capital			220,591
Retained earnings			70,402
Accumulated other comprehensive income			3,787
Total shareholders’ equity			296,608
Total liabilities and shareholders’ equity			405,354
Topic 606 [Member]
Current assets
Cash and cash equivalents		$ 81,157
Accounts receivable, net of allowances of $8,934 and $8,405, respectively		72,085
Inventories		78,992
Prepaid expenses and other current assets		25,877
Total current assets		258,111
Deferred income taxes		21,766
Other long-term assets		130,238
Total assets		410,115
Total liabilities		108,746
Shareholders’ equity
Common shares		1,828
Additional paid-in capital		220,591
Retained earnings		75,163
Accumulated other comprehensive income		3,787
Total shareholders’ equity		301,369
Total liabilities and shareholders’ equity		$ 410,115
Topic 606 [Member] | Impact of Adoption of ASC 606
Current assets
Accounts receivable, net of allowances of $8,934 and $8,405, respectively			8,648
Inventories			(2,338)
Total current assets			6,310
Deferred income taxes			(1,549)
Total assets			4,761
Shareholders’ equity
Retained earnings			4,761
Total shareholders’ equity			4,761
Total liabilities and shareholders’ equity			$ 4,761