Accumumlated Other Comprehensive Income / (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ (6,833)
Other comprehensive income before reclassifications	(37,874)
Amounts reclassified from accumulated other comprehensive income - net of tax	221
Net current-period other comprehensive income	(37,653)
Balance at the end of the period	(44,486)
Interest Rate Swaps
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(8,678)
Other comprehensive income before reclassifications	(54)
Amounts reclassified from accumulated other comprehensive income - net of tax	1,105
Net current-period other comprehensive income	1,051
Balance at the end of the period	(7,627)
Foreign Currency Translation
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(1,194)
Other comprehensive income before reclassifications	(36,303)
Amounts reclassified from accumulated other comprehensive income - net of tax	(884)
Net current-period other comprehensive income	(37,187)
Balance at the end of the period	(38,381)
Other
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	3,039
Other comprehensive income before reclassifications	(1,517)
Net current-period other comprehensive income	(1,517)
Balance at the end of the period	$ 1,522