Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Condensed Consolidated Statements of Comprehensive Income [Abstract]    
Net Income $ 9,803 $ 16,735
Other comprehensive income:    
Unrealized loss on marketable securities   (1,713)
Reclassification of previous unrealized gain on marketable securities into net income   (7,748)
Unrealized gain on interest rate swaps 215 258
Total other comprehensive income (loss) 215 (9,203)
Comprehensive income $ 10,018 $ 7,532