Geographic Information (Revenue by Geographic Locations) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Reportable_Segments	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | Reportable_Segments			1
Revenues from External Customers and Long-Lived Assets [Line Items]
Document Period End Date			Sep. 30, 2016
Revenue, Net, Increase (Decrease)	$ 7,795
External Revenues	74,608	$ 66,813	$ 218,248	$ 195,278
Long-lived assets	575,732	555,239	575,732	555,239	$ 575,732
Increase (Decrease) in Deferred Income Taxes			6,250	5,749
Goodwill, Transfers			0			$ (1,783)
Goodwill, Acquired During Period			21,789			$ 8,868
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			157,480	150,873
Long-lived assets	384,511	374,639	384,511	374,639	384,511
Long Lived Assets, Increase (Decrease)					(9,900)
Goodwill, Transfers					(28,800)
Goodwill, Acquired During Period					21,800
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			4,653	3,386
Long-lived assets	6,736	6,899	6,736	6,899	6,736
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			3,933	4,399
Long-lived assets	7,328	5,843	7,328	5,843	7,328
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			22,869	23,301
Long-lived assets	1,256	465	1,256	465	1,256
Effect of Exchange Rate on Revenue			(700)
BRAZIL
Revenues from External Customers and Long-Lived Assets [Line Items]
Effect of Exchange Rate on Revenue			(500)
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			4,384	3,855
Long-lived assets	17,505	68,805	17,505	68,805	17,505
Long Lived Assets, Increase (Decrease)					(51,300)
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			1,384	1,662
Long-lived assets	228	204	228	204	228
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net, Increase (Decrease)			7,500
External Revenues			10,076	2,548
Long-lived assets	80,636	73,921	80,636	73,921	80,636
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net, Increase (Decrease)			8,200
External Revenues			13,469	5,254
Long-lived assets	23,199	24,463	23,199	24,463	23,199
Dubai [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
External Revenues			0	0
Long-lived assets	$ 54,333	$ 0	$ 54,333	$ 0	54,333
Long Lived Assets, Increase (Decrease)					$ 54,300