Segment Reporting and Foreign Operations - Long-lived Assets by Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 234,803	$ 179,140	$ 128,055
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	176,644	134,393	97,881
Ireland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	48,182	36,008	22,203
Other Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 9,977	$ 8,739	$ 7,971