Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period			$ (16,734)
Other comprehensive income (loss) before reclassifications			(3,677)
Amounts reclassified from accumulated other comprehensive gain			481
Other comprehensive income (loss), net of tax	$ 1,713	$ 1,015	(3,196)	$ (1,444)
Balance at the end of the period	(19,930)		(19,930)
Defined Benefit Pension Plan
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period			(6,957)
Other comprehensive income (loss) before reclassifications			(2,110)
Amounts reclassified from accumulated other comprehensive gain			481
Other comprehensive income (loss), net of tax			(1,629)
Balance at the end of the period	(8,586)		(8,586)
Foreign Currency Translation Losses
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period			(9,858)
Other comprehensive income (loss) before reclassifications			(1,553)
Other comprehensive income (loss), net of tax			(1,553)
Balance at the end of the period	(11,411)		(11,411)
Unrealized Gains and (Losses) on Available-for-Sale Securities
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period			81
Other comprehensive income (loss) before reclassifications			(14)
Other comprehensive income (loss), net of tax			(14)
Balance at the end of the period	$ 67		$ 67