Investment in Real Estate - Schedule of Gross Investment in Real Estate (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Real Estate Properties [Line Items]
Land	$ 93.0	$ 89.7
Building and Improvements	905.3	812.6
Equipment	598.2	349.1
West Seventh St., Cincinnati, OH (7th Street)
Real Estate Properties [Line Items]
Land	0.9	0.9
Building and Improvements	110.6	110.6
Equipment	19.6	12.7
Parkway Dr., Mason, OH (Mason)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	20.2	20.2
Equipment	1.0	0.9
Industrial Rd., Florence, KY (Florence)
Real Estate Properties [Line Items]
Land	2.2	2.2
Building and Improvements	41.5	41.4
Equipment	3.3	3.0
Goldcoast Dr., Cincinnati, OH (Goldcoast)
Real Estate Properties [Line Items]
Land	0.6	0.6
Building and Improvements	6.7	6.7
Equipment	0.1	0.1
Knightsbridge Dr., Hamilton, OH (Hamilton)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	49.2	49.2
Equipment	4.4	3.7
E. Monroe St., South Bend, IN (Monroe St.)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	2.5	2.5
Equipment	0.3	0.1
Springer St., Lombard, IL (Lombard)
Real Estate Properties [Line Items]
Land	0.7	0.7
Building and Improvements	4.7	4.7
Equipment	7.6	5.7
Crescent Circle, South Bend, IN (Blackthorn)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	3.3	3.3
Equipment	0.4	0.1
Kingsview Dr., Lebanon, OH (Lebanon)
Real Estate Properties [Line Items]
Land	4.0	4.0
Building and Improvements	77.3	77.0
Equipment	7.6	5.5
McAuley Place, Blue Ash, OH (Blue Ash)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	0.6	0.6
Equipment	0.1	0.1
Westway Park Blvd., Houston, TX (Houston West 1)
Real Estate Properties [Line Items]
Land	1.4	1.4
Building and Improvements	84.8	84.4
Equipment	46.4	43.8
Westway Park Blvd., Houston, TX (Houston West 2)
Real Estate Properties [Line Items]
Land	2.0	2.0
Building and Improvements	22.6	22.5
Equipment	47.1	45.1
Westway Park Blvd., Houston, TX (Houston West 3)
Real Estate Properties [Line Items]
Land	18.4	18.4
Building and Improvements	4.0	0.0
Equipment	0.8	0.0
Southwest Fwy., Houston, TX (Galleria)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	68.6	68.6
Equipment	16.0	15.0
E. Ben White Blvd., Austin, TX (Austin 1)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	13.6	22.5
Equipment	1.0	1.2
S. State Highway 121 Business, Lewisville, TX (Lewisville)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	76.6	76.7
Equipment	24.9	22.8
Marsh Lane, Carrollton, TX (Marsh Ln)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	0.1	0.1
Equipment	0.6	0.5
Midway Rd., Carrollton, TX (Midway)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	2.0	2.0
Equipment	0.4	0.4
W. Frankford Rd., Carrollton, TX (Carrollton)
Real Estate Properties [Line Items]
Land	16.1	16.1
Building and Improvements	52.7	51.6
Equipment	116.5	85.3
Bryan St., Dallas, TX (Bryan St)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	0.0	0.1
Equipment	0.0	0.2
North Freeway, Houston, TX (Greenspoint)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	0.0	1.3
Equipment	0.0	0.0
South Ellis Street, Chandler, AZ (Phoenix 1)
Real Estate Properties [Line Items]
Land	14.8	14.8
Building and Improvements	56.7	56.4
Equipment	39.8	43.9
South Ellis Street, Chandler, AZ (Phoenix 2)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	16.0	13.2
Equipment	39.5	21.8
Westover Hills Blvd., San Antonio, TX (San Antonio 1)
Real Estate Properties [Line Items]
Land	4.6	4.6
Building and Improvements	32.1	32.1
Equipment	33.0	32.4
Westover Hills Blvd., San Antonio, TX (San Antonio 2)
Real Estate Properties [Line Items]
Land	7.0	7.0
Building and Improvements	0.0	0.0
Equipment	0.1	0.0
Metropolis Dr., Austin, TX (Austin 2)
Real Estate Properties [Line Items]
Land	2.0	2.0
Building and Improvements	23.2	23.2
Equipment	5.7	4.0
Myer Conners Rd (Wappinger Falls)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	11.3	0.0
Equipment	14.4	0.0
Madison Road (Totowa)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	28.3	0.0
Equipment	48.8	0.0
Commerce Road (Totowa)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	4.1	0.0
Equipment	1.0	0.0
Norden Place (Norwalk)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	18.3	0.0
Equipment	25.4	0.0
Riverbend Drive South (Stamford)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	4.3	0.0
Equipment	13.2	0.0
Omega Drive (Stamford)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	3.2	0.0
Equipment	1.5	0.0
Kestral Way (London)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	31.2	32.7
Equipment	0.8	0.7
Jurong East (Singapore)
Real Estate Properties [Line Items]
Land	0.0	0.0
Building and Improvements	8.4	9.0
Equipment	0.1	0.1
Ridgetop Circle, Sterling, VA (Northern Virginia)
Real Estate Properties [Line Items]
Land	7.0	7.0
Building and Improvements	19.2	0.0
Equipment	45.2	0.0
Metropolis Dr., Austin, TX (Austin 3)
Real Estate Properties [Line Items]
Land	8.0	8.0
Building and Improvements	0.0	0.0
Equipment	0.1	0.0
Metropolis Dr., Austin, TX (Austin 4)
Real Estate Properties [Line Items]
Land	3.3	0.0
Building and Improvements	7.4	0.0
Equipment	$ 31.5	$ 0.0