Summary of Significant Accounting Policies - Property, Plant and Equipment and Long-Lived Assets (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Accounting Policies [Abstract]    
Capitalization of internal use computer software $ 6,040 $ 4,897
Gain (loss) on disposal/write-down of property, plant and equipment (excluding real estate) 333 1,152
Gain on Sale of Real Estate, Net of Tax 0 7,468
Income tax expense on gain of real estate   $ 1,991