Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income		$ 48,888	$ 61,733	$ 51,565
Other comprehensive income:
Unrealized gain/(loss) on effective cash flow hedges, net of taxes $5,821, $1,734 and $109, respectively		13,981	3,395	23
Foreign currency translation adjustment		18,894	(9,236)	(12,510)
Retirement benefits, net of taxes $164, ($204) and $22, respectively		1,109	(439)	584
Reclassification adjustments
Realized loss/(gain) on cash flow hedges, net of taxes ($2,110), ($1,190) and ($49), respectively(1)	[1]	(4,789)	(1,479)	(71)
Retirement benefits, net of taxes $104, $63 and $53, respectively(2)	[2]	152	27	158
Total other comprehensive income/(loss)		29,347	(7,732)	(11,816)
Total comprehensive income		$ 78,235	$ 54,001	$ 39,749

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjE4MjMzOGNjMDZhZDQ5MmM5MmQ3ZGZjZmU4MmZlYTBifFRleHRTZWxlY3Rpb246RERBNzRDRkREREJENThDMTgxNzI3OThBMDFGRDRDNTgM}

[2] These are reclassified to net income and are included in the computation of net periodic pension costs in the consolidated statements of income. See Note 18 to the consolidated financial statements.