Accumulated Other Comprehensive Income (Details2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Reclassifications out of accumulated other comprehensive income, net of tax
Interest expense	$ 2,368	$ 3,182
Provision for income taxes	5,174	3,541
Net income	(10,649)	(7,028)
Total reclassifications for the period	45
Gains and losses on cash flow hedges
Reclassifications out of accumulated other comprehensive income, net of tax
Total reclassifications for the period	45
Gains and losses on cash flow hedges | Interest rate contracts
Reclassifications out of accumulated other comprehensive income, net of tax
Total reclassifications for the period	45
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income | Interest rate contracts
Reclassifications out of accumulated other comprehensive income, net of tax
Interest expense	73
Provision for income taxes	(28)
Net income	$ 45