Income Taxes - Deferred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Income taxes
Change in valuation allowance for deferred tax asset	$ 2,500
Classification of deferred tax amounts
Non-current assets		$ 18,638	$ 13,280
Non-current liabilities		17,829	17,928
Deferred tax assets:
Allowances for doubtful accounts		2,046	1,976
Deferred branch tax benefit		15,859	15,813
State tax Federal deduction true-up		70
Deferred income			29
Fixed assets		43	39
Accrued expenses		1,204	1,440
Foreign tax credit		11,449	5,572
Stock compensation		3,865	3,465
Pension		690	651
Intangibles		2,286	2,376
Other DTA		533
Deferred tax assets, gross		38,045	31,361
Deferred tax liabilities:
Prepaid expenses		(505)	(196)
Intangibles		(20,910)	(23,000)
Property and equipment		(3,117)	(3,098)
Amortization expense		(12,704)	(9,715)
Total deferred tax liabilities		(37,236)	(36,009)
Total deferred tax assets		$ 809
Net deferred tax liabilities			$ (4,648)