XML 43 R56.htm IDEA: XBRL DOCUMENT v2.4.1.9
Contractual Coupon Interest Expense (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Debt Instrument [Line Items]      
Contractual coupon interest expense $ 5,063us-gaap_InterestExpenseDebt $ 5,063us-gaap_InterestExpenseDebt $ 3,488us-gaap_InterestExpenseDebt
Accretion of discount on the liability component $ 3,973us-gaap_AccretionExpense $ 3,710us-gaap_AccretionExpense $ 2,411us-gaap_AccretionExpense