Results of Operations for Beecher (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Weighted average number of shares outstanding:
Basic	140,836	139,086	140,816	139,044
Diluted	143,021	141,828	142,938	141,664
Beecher [Member]
Subsequent Event [Line Items]
Total revenues	$ 354,873		$ 718,966
Income before income taxes	90,152		193,575
Net income	$ 54,382		$ 116,887
Net income per share:
Basic	$ 0.38		$ 0.81
Diluted	$ 0.37		$ 0.80
Weighted average number of shares outstanding:
Basic	140,836		140,816
Diluted	143,021		142,938