Segment Reporting and Foreign Operations - Long-lived Assets by Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 244,171	$ 243,270	$ 234,803
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	177,627	178,130	176,644
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	49,708	50,274	48,182
Other Foreign Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 16,836	$ 14,866	$ 9,977