Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period	$ (14,957)
Other comprehensive income (loss) before reclassifications	754
Amounts reclassified from accumulated other comprehensive income	1,020
Other comprehensive gain (loss), net of tax	1,774	(4,072)	(1,710)
Balance at the end of the period	(13,183)	(14,957)
Defined Benefit Pension Plan
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period	(11,540)
Other comprehensive income (loss) before reclassifications	2,075
Amounts reclassified from accumulated other comprehensive income	1,020
Other comprehensive gain (loss), net of tax	3,095
Balance at the end of the period	(8,445)
Foreign Currency Translation Losses
Changes in accumulated other comprehensive income (loss), net of tax
Balance at the beginning of the period	(3,876)
Other comprehensive income (loss) before reclassifications	(1,193)
Other comprehensive gain (loss), net of tax	(1,193)
Balance at the end of the period	(5,069)
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	459
Other comprehensive income (loss) before reclassifications	(128)
Other comprehensive gain (loss), net of tax	(128)
Balance at the end of the period	$ 331