Earnings Per Share , Calculation of Numerator and Denominator (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator
Basic earnings: net income attributable to common stockholders									$ 160,265	$ 105,493	$ 160,265	$ 105,493	$ 65,021
Income (loss) Attributable to Common Stockholders Allocable To Non Vested Restricted Shares									(1,170)	(831)			(455)
Net income attributable to common shareholders after restricted stock allocation									159,095	104,662			64,566
Allocation of income to restricted stock awards									1,170	831			455
Diluted earnings: net income attributable to common stockholders after allocation									$ 160,265	$ 105,493			$ 65,021
Denominator
Weighted average common shares outstanding									88,460	81,387	88,460	81,387	76,084
Add: dilutive stock options									1	2			2
Add: dilutive restricted stock									454	651			625
Diluted weighted average common shares and securities									88,915	82,040	88,915	82,040	76,711
Basic (in USD per share)	$ 0.31	$ 0.63	$ 0.46	$ 0.40	$ 0.11	$ 0.56	$ 0.25	$ 0.38	$ 1.80	$ 1.29	$ 1.80	$ 1.29	$ 0.85
Diluted (in USD per share)	$ 0.31	$ 0.63	$ 0.46	$ 0.40	$ 0.11	$ 0.56	$ 0.25	$ 0.38	$ 1.80	$ 1.29	$ 1.80	$ 1.29	$ 0.85