|
Investments - Summary of Company's Investment Securities (Detail) (USD $)
In Millions, unless otherwise specified
|
9 Months Ended |
12 Months Ended |
|
Feb. 28, 2014
|
May 31, 2013
|
| Summary of Investment Holdings [Line Items] |
|
|
| Available-for-sale, Amortized Cost |
$ 17.2 |
$ 17.2 |
| Available-for-sale, Unrealized Gains |
8.2 |
4.8 |
| Available-for-sale, Unrealized Losses |
(0.2) |
0 |
| Available-for-sale, Fair Value |
25.2 |
22.0 |
| Trading, Amortized Cost |
1.6 |
0.8 |
| Trading, Realized Gains |
0.2 |
0.2 |
| Trading, Realized Losses |
0 |
0 |
| Trading, Fair Value |
1.8 |
1.0 |
|
Equity securities [Member]
|
|
|
| Summary of Investment Holdings [Line Items] |
|
|
| Available-for-sale, Amortized Cost |
0.2 |
0.2 |
| Available-for-sale, Unrealized Gains |
0.5 |
0.2 |
| Available-for-sale, Unrealized Losses |
(0.2) |
0 |
| Available-for-sale, Fair Value |
0.5 |
0.4 |
| Trading, Amortized Cost |
1.6 |
0.8 |
| Trading, Realized Gains |
0.2 |
0.2 |
| Trading, Realized Losses |
0 |
0 |
| Trading, Fair Value |
1.8 |
1.0 |
|
Time deposit [Member]
|
|
|
| Summary of Investment Holdings [Line Items] |
|
|
| Available-for-sale, Amortized Cost |
15.9 |
15.9 |
| Available-for-sale, Unrealized Gains |
1.1 |
0.1 |
| Available-for-sale, Unrealized Losses |
0 |
0 |
| Available-for-sale, Fair Value |
17.0 |
16.0 |
|
Greek bonds [Member]
|
|
|
| Summary of Investment Holdings [Line Items] |
|
|
| Available-for-sale, Amortized Cost |
1.1 |
1.1 |
| Available-for-sale, Unrealized Gains |
6.6 |
4.5 |
| Available-for-sale, Unrealized Losses |
0 |
0 |
| Available-for-sale, Fair Value |
$ 7.7 |
$ 5.6 |