Earnings Per Share (Details) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Weighted-average shares outstanding for basic and diluted net income per share
Net income	$ 4,415,000	$ 10,486,000	$ 3,987,000	$ (647,000)	$ (16,322,000)	$ 7,302,000	$ 8,315,000	$ 6,362,000	$ 18,241,000	$ 5,657,000	$ 27,332,000
Basic net income per share:
Basic (in usd per share)	62,345,000	62,093,000	61,658,000	61,179,000	60,899,000	60,867,000	60,461,000	60,312,000	61,818,000	60,635,000	60,259,000
Earnings Per Share, Basic	$ 0.07	$ 0.17	$ 0.06	$ (0.01)	$ (0.27)	$ 0.12	$ 0.14	$ 0.11	$ 0.30	$ 0.09	$ 0.45
Diluted net income per share:
Basic (in usd per share)	62,345,000	62,093,000	61,658,000	61,179,000	60,899,000	60,867,000	60,461,000	60,312,000	61,818,000	60,635,000	60,259,000
Weighted-average shares outstanding - Diluted	62,348,000	62,093,000	62,052,000	61,676,000	60,899,000	61,279,000	61,194,000	61,064,000	62,010,000	61,233,000	60,849,000
Diluted (in usd per share)	$ 0.07	$ 0.17	$ 0.06	$ (0.01)	$ (0.27)	$ 0.12	$ 0.14	$ 0.10	$ 0.29	$ 0.09	$ 0.45