Discontinued Operations and Divestitures - Gains on Disposals of Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Discontinued Operations and Disposal Groups [Abstract]
Gain on disposal of discontinued operations, before income tax expense									$ 133	$ 107,533	$ 143
Income tax expense									34	49,197	52
Gain on disposal of discontinued operations, net of tax	$ (7)	$ 607	$ (27)	$ (474)	$ 93	$ 56,315	$ 1,905	$ 23	$ 99	$ 58,336	$ 90