Industry Segment and Geographic Area Data	3 Months Ended
	Jun. 30, 2020
Segments, Geographical Areas [Abstract]
12. Industry Segment and Geographic Area Data	12. Industry Segment and Geographic Area Data     United States   Canada   Consolidated     (Unaudited)     (All amounts are in thousands of U.S. $'s) Quarter Ended June 30, 2020             Total revenues $ 942,803 $ 44,434 $ 987,237 Depreciation and amortization, net of gains on disposal   168,526   3,777   172,303 Interest expense   38,654   867   39,521 Pretax earnings   111,949   2,369   114,318 Income tax expense   25,783   809   26,592 Identifiable assets   13,279,882   432,477   13,712,359               Quarter Ended June 30, 2019             Total revenues $ 1,028,574 $ 50,675 $ 1,079,249 Depreciation and amortization, net of gains on disposal   141,898   3,144   145,042 Interest expense   38,220   668   38,888 Pretax earnings   170,847   3,867   174,714 Income tax expense   41,114   1,178   42,292 Identifiable assets   12,076,714   398,030   12,474,744