Income Taxes - Additional Information (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes
Deferred tax assets, operating loss carryforwards	$ 7,279,000	$ 9,387,000
Credit carry-forwards	22,743,000	35,082,000
Deferred tax asset valuation allowance	11,024,000	10,266,000
Foreign tax credit carry-forwards	19,375,000
Research and development credits	4,311,000
Foreign income tax expense	13,729,000	12,482,000	$ 6,981,000
Alternative minimum tax credit carry-forwards	882,000
Income tax provision on foreign earnings to be permanently reinvested outside US	0
Undistributed Earnings of Foreign Subsidiaries	133,074,000
Unrecognized tax benefits	12,347,000
Accrued for interest and penalties related to uncertain income tax	$ 1,772,000	1,206,000
Maximum
Income Taxes
Open Tax Year	2008
Minimum
Income Taxes
Open Tax Year	2015
Non-U.S. | Income Tax Benefit
Income Taxes
Effects of change in accounting method		16,305,000
Non-U.S. | Operating Carry Forward
Income Taxes
Effects of change in accounting method		(8,214,000)
Non-U.S. | Foreign Tax Credit Carryforward
Income Taxes
Effects of change in accounting method		24,519,000
China
Income Taxes
Tax expense relating to earnings not indefinitely reinvested outside US		$ 7,461,000