Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information [Line Items]
Total revenues	$ 179,881	$ 187,966	$ 176,753	$ 183,775	$ 165,312	$ 175,064	$ 168,383	$ 174,947	$ 728,375	$ 683,706	$ 577,009
Gross Profit	62,843	64,779	56,597	70,332	58,369	53,882	41,657	52,535
Consolidated income from continuing operations	28,713	34,936	21,786	40,470	29,015	21,492	6,298	17,654	77,247	63,747	41,957
Net income available for Common Shares	$ 24,160	$ 29,872	$ 17,860	$ 35,027	$ 24,275	$ 16,009	$ 2,063	$ 12,432	$ 125,905	$ 59,846	$ 26,346
Weighted average Common Shares outstanding - Basic	83,003	83,021	83,021	83,026	82,569	82,380	82,262	82,176	83,018	82,348	71,182
Weighted average Common Shares outstanding - Diluted	91,334	91,259	91,128	91,060	90,944	90,894	90,780	90,738	91,196	90,862	80,660
Net income (loss) per Common Share outstanding-Basic	$ 0.29	$ 0.36	$ 0.22	$ 0.42	$ 0.29	$ 0.19	$ 0.03	$ 0.15	$ 1.29	$ 0.67	$ 0.32
Net income (loss) per Common Share outstanding-Diluted	$ 0.29	$ 0.36	$ 0.21	$ 0.42	$ 0.29	$ 0.19	$ 0.02	$ 0.15	$ 1.28	$ 0.66	$ 0.32