Earnings Per Share Attributable to Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 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	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income attributable to:
Basic													$ 149,039	$ 121,479	$ 75,027
Diluted													$ 149,039	$ 121,479	$ 74,875
Weighted average number of shares outstanding:
Basic													108,519,739	108,063,349	107,044,348
Diluted													109,759,123	109,388,236	108,113,151
Per Share Amount
Basic	$ 0.47	$ 0.23	$ 0.50	$ 0.17	$ 0.33	$ 0.21	$ 0.42	$ 0.16	$ 0.34	$ 0.10	$ 0.16	$ 0.10	$ 1.37	$ 1.12	$ 0.70
Diluted	$ 0.47	$ 0.23	$ 0.49	$ 0.17	$ 0.32	$ 0.21	$ 0.42	$ 0.16	$ 0.34	$ 0.09	$ 0.16	$ 0.10	$ 1.36	$ 1.11	$ 0.69
Share Units [Member]
Net income attributable to:
Effect of dilutive securities															$ (152)
Weighted average number of shares outstanding:
Effect of dilutive securities:													458,763	459,503	353,880
Stock Options [Member]
Weighted average number of shares outstanding:
Effect of dilutive securities:													780,621	865,384	714,923
Per Share Amount
Effect of dilutive securities:													(0.01)	(0.01)	(0.01)