Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2012 Reportable_Segments	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segments													1
External Revenues	$ 54,023	$ 53,804	$ 47,716	$ 43,827	$ 44,050	$ 42,602	$ 42,267	$ 40,050	$ 35,097	$ 33,281	$ 32,207	$ 31,603	$ 199,370	$ 168,969	$ 132,188
Long-lived assets	435,277				347,365				242,518				435,277	347,365	242,518
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													140,933	120,780	93,719
Long-lived assets	317,338				259,425				151,355				317,338	259,425	151,355
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													6,395	836	707
Long-lived assets	9,738				0				0				9,738	0	0
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													8,227	10,504	4,874
Long-lived assets	12,726				14,179				18,478				12,726	14,179	18,478
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													36,330	31,991	27,253
Long-lived assets	1,267				1,286				1,525				1,267	1,286	1,525
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													2,827	2,943	4,156
Long-lived assets	70,173				63,866				67,781				70,173	63,866	67,781
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													2,205	1,915	1,479
Long-lived assets	240				233				40				240	233	40
India
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													233	0	0
Long-lived assets	11,784				8,376				3,339				11,784	8,376	3,339
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues													2,220	0	0
Long-lived assets	$ 12,011				$ 0				$ 0				$ 12,011	$ 0	$ 0