Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Increase (decrease) in accumulated other comprehensive income (loss) [Roll Forward]
Balance at the beginning of the year	$ (6,344)	$ (3,072)	$ (4,949)
Unrealized gains (losses)	561	(509)	1,404
Unrealized gains in fair value	123	917	315
Unrecognized amounts from defined benefit pension plans	(2,444)	(6,111)	790
Tax effect	989	2,431	(632)
Net of tax amount	(771)	(3,272)	1,877
Balance at the end of the year	(7,115)	(6,344)	(3,072)
Foreign Currency Translation Adjustments
Increase (decrease) in accumulated other comprehensive income (loss) [Roll Forward]
Balance at the beginning of the year	2,950	3,459	2,055
Unrealized gains (losses)	561	(509)	1,404
Unrealized gains in fair value	0	0	0
Unrecognized amounts from defined benefit pension plans	0	0	0
Tax effect	0	0	0
Net of tax amount	561	(509)	1,404
Balance at the end of the year	3,511	2,950	3,459
Interest Rate Cash Flow Hedges
Increase (decrease) in accumulated other comprehensive income (loss) [Roll Forward]
Balance at the beginning of the year	(77)	(645)	(840)
Unrealized gains (losses)	0	0	0
Unrealized gains in fair value	123	917	315
Unrecognized amounts from defined benefit pension plans	0	0	0
Tax effect	(46)	(349)	(120)
Net of tax amount	77	568	195
Balance at the end of the year	0	(77)	(645)
Defined Benefit Pension Plans
Increase (decrease) in accumulated other comprehensive income (loss) [Roll Forward]
Balance at the beginning of the year	(9,217)	(5,886)	(6,164)
Unrealized gains (losses)	0	0	0
Unrealized gains in fair value	0	0	0
Unrecognized amounts from defined benefit pension plans	(2,444)	(6,111)	790
Tax effect	1,035	2,780	(512)
Net of tax amount	(1,409)	(3,331)	278
Balance at the end of the year	$ (10,626)	$ (9,217)	$ (5,886)