CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME    
Net income $ 26,457 $ 23,527
Other comprehensive income, net:    
Amortization of actuarial loss on defined benefit pension plan, net 68 5
Unrealized (loss) gain on marketable securities, available-for-sale, net (19) 188
Other comprehensive income, net 49 193
Comprehensive income $ 26,506 $ 23,720